Rinnai Continuum Model 2532, indoor mount, residential application
I’m trying to help a galpal who has gotten swindled by numerous contractors on a sweet log cabin they’d hoped would be her and her husband’s forever home, but he’s going deep into Alzheimers and the problems are surfacing left and right. She’s got her hands full taking care of him, so i’m trying to help out as her area of expertise is ballet.
The most pressing issue right now is the tankless heater used for both domestic hot water and the RFH, about 1200 SF of under-slab in the walk-out basement and the same SF of staple-up with alum flanges underneath the plank floor above. The first time a problem surfaced was when all the heating zones were off and she got no hot water at the taps. She got someone in to cure that; i don’t know how. The heater cycles very frequently to provide space heating. The bottom floor roasts when the top floor is still a bit chilly.
All the manifolds were buried behind the sheetrock, the exhaust vent was never trimmed to length so that it sticks out beyond the exterior about 2 feet, the Romex is unprotected outside the wall, and there are four pumps…a main one and one for each zone – isn’t this overkill? Anyway, the oddest and sloppiest installation i’ve ever seen.
The plumber who contracted the work has a master plumber’s license, but now lives in Jamaica…hard to get him back to fix it. There is some trouble in that the BI didn’t do a final inspection, though a permit was pulled, and now is being very uncooperative with my friend. She has finally found a plumber willing to tackle the mess, but asked me to be there to translate for her when he comes tomorrow afternoon. I’ve been reading the technical manuals on this heater, but if i read the information correctly, it can’t be used for space heating in a residential application. Before anything else happens, i would like to know if this elemental fact is correct.
Also any other words of plumbing wisdom about this situation and/or a possible salvage operation would be welcome. My inclination would be to split the domestic off the space heating and deal with them seperately…smart?no? I will post pictures tomorrow as i think a lot more of the wall will be coming off to see what evils lie buried.
Replies
bump
You posted late and the main crowd usually doesn't arrive 'til afternoon so hang on.
Trying to think of the regulars who might have a working knowledge of this but come up blank.
If time pressured you might want to rip off an email to Bill Hartmann/BT-same or Bob Walker/BT-rjw.
Cheers
'Nemo me impune lacesset'No one will provoke me with impunity
I'm just heading up to my friend's house now, so i'll check in on Leanna's computer from time to time. I'll ping Bill and Bob...good idea.
Or you might want to do a search under 'radiant floor' to see who seemed experienced and try an email that way.
'Nemo me impune lacesset'No one will provoke me with impunity
I know everything there is to know about everything,.. Except for RFH and tankless water heaters.Sorry.
It was just a pot shot. She sounded time pressured.
be the only person that really knows everything is seeyou since he invented it.
'Nemo me impune lacesset'No one will provoke me with impunity
standing...
staring into nowhere at my feet...
hat held over my heart...
awe struck expression of disbelief on my face....
gulpin' instead of swallowin'... with a sense of forboding despair...
BILL YA CAN'T DO THIS TO US....Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!<!----><!---->
Forget the primal scream, just ROAR!!!
The most pressing issue right now is the tankless heater used for both domestic hot water and the RFH, about 1200 SF of under-slab in the walk-out basement and the same SF of staple-up with alum flanges underneath the plank floor
Built a few homes in the 80s with RFH, but I am no expert, I would think you would need two different temptures of output for the above. We would always use 2 heaters one for the water & one for the floors.
In one house we used standard water heaters, one set on low for the floors & the other set high for the domestic hot water.
Try this site http://www.alsheating.com/RinnaiHeater.htm Old Al may be of some help to you.
That's one of the plumbing sites i enjoy reading a great deal - fun and informative. No joy there, though - it only speaks to the domestic uses of the heater, but doesn't explicitly state it can't be dual use.
I suppose the next thing will be to call Rinnai and ask some questions - it's just that i've gotten more help and better answers here in the past for my own fixes than from the dealers. ;^)
Back to my sander...we're finishing the deck today bec my galpal made the mistake of paying Deck Guy before he finished the job. :^)
It does sound like you have a system that wants two temperatures getting one, and you are using a heat source that is not so great for radiant. It can, I believe, be made to work, but it's not usually worth it to try.If it's all you've got, you could make it work until it dies and then replace it with something more appropriate though. It might last quite awhile.. or not. Hard to say.. not an ideal application for the on demand heaters.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
I'm curious on how it's piped.
If it's an open or closed system.
Since a radiant floor system runs at lower temps than your domestic hw I wonder if there is a mixing valve of some sort to knock down the temp.
I too am not familiar with this type of application.
I usually see boilers with a hot water maker on the system verses a domestic system providing hydronic heat.Do you look to the government for an entitlement, or to GOD for empowerment. BDW
That's a very good question. The water temp may be too high for the slab and too low for the upper low, pretty easily.Also whether there is an HE in use or not is pretty important. There definitely should be. Usually on these systems though, there isn't, because it was installed this way to "save money".For low loads domestic heaters can provide radiant heating pretty well... still need to design the system properly, but it can be done. But as load grows, the less appropriate this choice becomes, IMHO.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
I've got the actual square footage of the house now, which is 1300 on each floor, log home construction, in MT at 4000' elevation. Good quality French doors and windows, but lots of them on the upper floor. Ball-parking it - and i won't hold you to it - does this sound like the size of system that the spec'd Rinnai could handle all by itself, in your opinion? The floor and domestic are completely open to one another. I don't know if there is a cold water mixing valve to temper the floor. I will find out today.
You are well into a size in which I would use a proper modulation/condensing boiler, and jump your efficiency up a good 15% in the process.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
If you have the patience, search the radiant threads in the Energy section.
Someone there was a strong supporter of tankless water heaters (over boilers) and had installed such systems. I think he was from Colorado.
Mike
Trust in God, but row away from the rocks.
I will do as you suggest in the energy threads - oy! lotsa reading there. I've also got an email into Rinnai, and the name and phone number of the manufacturer's rep for this area to call tomorrow. The latest contractor (#3?) who promised to show up this afternoon called a half hour before he was due and bailed out. I have a sneaking suspicion i am going to become very well acquainted with this RFH system. I installed my own boiler, controls, etc. and baseboards a few years back, no problems, but it was lots easier going at it from scratch than figuring out what someone else did.
Any chance you could post a photo or two of the system?
We were too pooped yesterday after sanding to get the pix, but i'm heading up there today to open up the wall and document what's there with pictures before anything happens. I'll post when i get back this afternoon. It turns out i was wrong about something i earlier posted: the domestic HW is NOT available one when the floor zones are not calling for heat - that problem was never fixed. My friend had to heat water on the stove last night to bathe her husband when he had an accident. I told her she could crank the thermostat and she could get HW at the taps, but it was 1:30am when it happened and she wasn't thinking well.
I take back what I said about not know anything about radiant or hydronic heating systems.I do know that there is a website and forum that specialises in that.http://www.heatinghelp.com
I just got in from breaking sheetrock, isolating cirulators, and running stairs. Today i picked up the book written by the guy, Dan Holohan, who maintains that website: Hydronic Radiant Heating - A Practical Guide for the Nonengineer Installer. At least i'm fully qualified to read it. :^)
A pic is attached. There are three heating zones (downstairs, upstairs, and bedrooms - thank heavens this much makes sense) with circulators, Taco 007, for each, marked by small "o". There is another domestic HW zone, without a circulator, at "x". There is a circulator, Taco 011, on the cold water inlet, marked large "O". The Big Mama 011 circulator (on the cold inlet) runs any time there is a call for radiant heat. Even in zones that are not calling for heat, hot water is pushed past all the impellers of the Baby 007 circulator to create heated zones in effect. I tested this by removing a 007 circulator electrically from its zone...the pipes still got hot almost as efficiently as the zone in which the 007 circulator was running. I believe this is the problem with the bottom floor (walkout basement, windows one side only) being so much hotter than the top floor (French doors and many windows), bec even with the basement thermostat off, the basement would get much hotter than the upstairs, with only the upstairs calling for heat. I may be naive, but wouldn't a zone control valve be a better solution for making water go/not go where it should compared to sticking an impeller in the line? If the 011 circulator on the cold inlet is removed electrically from the control panel, a call for heat results in nothing. A call for DHW does NOT trigger the 011 circulator, but water is pulled past it anyway to the Rinnai and on to the tap. There is a three-zone control box, through which the three heating zones are routed. The DHW zone does not go through this box, though the circuits inside indicate one of them is meant for DHW, since it explains how that circuit overrides a call for radiant heat. I *suspect* the installer brought the wrong controller box with him and made the best of it....thoughts?Two odd things happened while playing with this today...once only, while the kitchen hot tap was running, the water ran cold: the Rinnai flame went out for no reason i could discern. I could not get a repeat of the fault, though i replicated my actions. One other time, when there was no call for heat or DHW, the fan for the Rinnai just kicked on, with no flame. (Fan normally should run a few seconds before flame, and for about a minute after flame goes out.)It had been suggested to check if the water pressure is too low at this house, causing flow problems in turn causing ignition problems. However, the pressure tank is new, and the pressure switch operated between 35-55 PSI consistently today.This Rinnai is rated at 180,000 BTU's, which seems like it ought to be able to keep up with demand.Check valves: there is a check valve - two actually - to keep the cold water flowing in one direction only, but there is no check valve to keep DHW and radiant floor water separate. Not sure if this is a problem if the RFH is being used frequently, but when RFH is not being used in summer...not sure that stale water leaking back into HW supply is a Good Thing. Opinions? Facts? (Please forewarn me which is which. I'm very gullible.)I'm retiring to my 6' Kohler soaker tub now, filled with endless hot water from my Aquastar, plumbed by me, which actually works - let's hear it for DIY! - to read a steamy story featuring Wirsbo and Erie, the twin goddesses of Thermopolis. Ahhhhhhhhhhhhh, that feels better...
Even without know anything about those systems I am qualified to give you an expert diagnosis. IT IS ALL F*D UP!Some queations and commentsEach heating loop has what looks like a pressure regulator. Is that what it is? That makes no sense. Specially in a heating loop. What I would expect is a tempering valve. However, they take 3 connections. They allow the water in the loop to circulate, plus add some hot water from the heater as needed to bring that to the RFH temp which is much lower than DHW. That is unless the heater operating temp is controlled by the controller to drop it back when it is only doing RFH.What are the manifolds.I am guess that the left side has domestic hot and cold allthough I can't see the hot side manifold.Off the cold water pipe to the heater (the center pipe if I am reading this correctly) it T's at the left wall and looks like and elbow going into the wall. Where does that go? And if I am tracking it the cold water also has to go through the master circulator.What is that filter for? I am guessing that the bottom right conner is the well tank. Forgetting the RFH just the domestic cold water does not make sense. It appears that the pipe goes into the wall and back out 3 or 4 times. And just for grins what is that galvanized pipe in the lower left bottom?Now back to RFH. I am guessing that the manifolds on the right side are supply and returns for on floor and that there are others on other floors.And where is the return line from the RFH loops. I can't see what apperas to be any. It should come back to the cold water side of the heater.The way that I would expect something like this to be connected would be a T off the hotwater side to the master circulator, if needed, then break down to the different zones, (plus zone valves/circulators & tempering valves as needed) then combine all back and T back into the cold water side. With a check valve or two where it connects to the cold and water side. The domestic cold water would t off before the heater and DHW would T-off right out of the heater. And a flow switch on the DHW would conntect to the controller to shut off RFH while DHW is being called for.If the
I'll take some more pics with the wall opened up of the manifolds. The "elbow going into the wall" turns UP to become the supply side of the DHW manifold. I think only the cold water to the boiler goes through the master circulator, not the supply to the fixtures. I think that's the galvanized pipe you mention. Filter took the place of the water softener that was removed. There are two ball valves shutting it off, and a bypass as well, also with a ball valve. Don't even go there for now. <G> "Yep", on all those regulators. I didn't know enough to comment on why there should be a flock of them as the three-zone boiler installation i did myself only required one on the cold water inlet. The controller has a specific connection for the DHW to take priority over the RFH, but one of the heating zones is wired in that spot. The DHW is on its own, no controller connection at all. Aside: I was reading the original contractor's bid, which included over $1700 for fixture allowance. My friend paid for all the fixtures herself and has receipts.This is a pic of the manifold for the slab. I thought the shut-offs should be on the supply side, but they are actually on the return side...?
My impression is that the reason for the DHW priority is that the WH can only put out so many BTU's. So when DHW is need that the circulars/valves for the RFH are disabled so that all heating goes to DHW. That requires some signal to tell it when DHW is needed. AFAIK that is typically done with a flow switch in the DHW feed.""Yep", on all those regulators. I didn't know enough to comment on why there should be a flock of them as the three-zone boiler installation i did myself only required one on the cold water inlet."I don't think that you need any. But in a closed loop system you might have a water makeup feed control. Don't know if you can do that with a regular and/or if they might look like regulaters." I think that's the galvanized pipe you mention."Why in the H*LL is there even any galvanized at all. Make sure that it has dielectric unions where it meets up with the copper or you will have worse problems in the future."I'll take some more pics with the wall opened up of the manifolds. The "elbow going into the wall" turns UP to become the supply side of the DHW manifold. I think only the cold water to the boiler goes through the master circulator, not the supply to the fixtures. I think that's the galvanized pipe you mention."What I am looking it is the from the center pipe to the WH (which is feed by the big pump so I assume that it is the CW feed) is a T and with a hoirontal to the left.And then it appears that there are one are two sections of "brass". Might be a check valve and union. But it is hidden behind the thermometer and the PT safety valve (ps, you should check and make sure that it is the right kind. I think that for this kind of system it is different than one that screws into the side of a storage tank type WH, but I might be wrong).then it runs to the wall and T's. To the left it it appears to elbow into the wall, but it is partially hidden by the filter.To the right it appears to turn 90 horizontal and then 90 veritical and connect to the cold water manafold. But it might run past it. That is what it appears to me to be supplying cold water and it runs through the big circulator.
PS, within the last couple of years JLC (I think that it was JLC and not FHB) has had an article or two on "plumbing" for RFH. It shows how different systems need one or sometimes more circulators and where checkvavles and tmpering valve.go to http://www.jlconline.com and then research and search for them.I think that it is $3.50 per article if you don't have access to the mags.
That requires some signal to tell it when DHW is needed. AFAIK that is typically done with a flow switch in the DHW feed.
The controller is an Erie SR301, for three zones, with domestic HW priority on Zone 1, if desired, by moving a jumper. That leaves only two zones for heating...and i've got three heating zones to control. Na...that won't work...
But in a closed loop system you might have a water makeup feed control. Don't know if you can do that with a regular and/or if they might look like regulaters.
It's an open system as of now, so no make-up waer was needed or air scoops or....., but those regulators are just regulators, not for make-up water.
The routing stuff i think i already answered....CW inlet from the wall, T to ball valve and laundry, back from laundry to master circulator to heater; and from ball valve on to pressure tank.
Edit: no one's asked, but that big pipe coming out of the floor with the fan in-line tot he left of the pressure tank: radon mitigation, $800. There is no record or memory of a radon test being done, he just sold her on the idea.
Edited 4/24/2006 2:01 am ET by splintergroupie
Some nude photos:
I'm posting rather large sizes for clarity; hope this is not a big problem for the dial-uppers. And i'm sorry i took so long, but i worked a spay/neuter clinic the last two days, plus just buried my cat who lost his duel with FIV. Ob la di, ob la da...
(Also, in IE, i find that i can't upload a photo for some reason. In Mozilla, i can't format except with HTML. Gawd, i hate Desparo....)
Each heating loop has what looks like a pressure regulator. Is that what it is?<!----><!----><!---->
Yes. One on each zone. I don't get it either, but maybe someone can offer the rationale. <!----><!---->
That is unless the heater operating temp is controlled by the controller to drop it back when it is only doing RFH.<!----><!---->
The controller gives priority to a HW feed over the heating zones...but they wired a zone into it, not the HW, which doesn't run through the controller at all. I don't get this either. Temp output can only be the same at all outfeeds of the tankless, as it is presently set up.<!----><!---->
What are the manifolds....And where is the return line from the RFH loops.<!----><!---->
Upper right ones, white PEX, go to upper floor radiant, two zones...don't know yet why they appear to be unbalanced in number. Blue and Orange PEX is the kitchen/bath H&C supply upstairs and to laundry in the pictured room (orange and blue pipe heading to the right under the sheetrock), and i believe to the bath downstairs. Unfortunately, there is no paper plan, so i'm doing a bit of WAGing on a few of the connections. <!----><!---->
There is a manifold for supply and return on the east wall (the one with the pressure tank) for one zone, i.e. the downstairs radiant. All orange pipe. <!----><!---->
Off the cold water pipe to the heater (the center pipe if I am reading this correctly) it T's at the left wall and looks like and elbow going into the wall. Where does that go?<!----><!---->
The cold pipe goes into the bathroom on the other side of the wall. (Cold also enters the bathroom on the east/pressure tank wall.) <!----><!---->
As a point of interest, the whole-house, ball-valve shut-off is placed AFTER the T which feeds the laundry, and from there to the master circulator. Thar she blows...<!----><!---->
And if I am tracking it the cold water also has to go through the master circulator.<!----><!---->
Yes.<!----><!---->
And just for grins what is that galvanized pipe in the lower left bottom?<!----><!---->
The galv pipe on lower left of the wall with the Rinnai is from the well head. And yes! It goes directly galv to bronze and back again, with some yellow PEX (gas line?) for good measure! And the union leaks!<!----><!---->
The way that I would expect something like this to be connected would be a T off the hotwater side to the master circulator, if needed, then break down to the different zones, (plus zone valves/circulators & tempering valves as needed)<!----><!---->
What is the need for the master circulator at all? In this case, without zone valves on the heating zones, it pumps heated water to all the zones regardless of which one is calling for heat. However, it doesn't operate when DHW is called for, but [usually] one gets DHW even though the master circulator doesn't switch on, past its idling impeller, i'm surmising. <!----><!---->
<!----><!---->
OK the system is wrong.
But it's eath day & my dw birthday-- I promised I would get the trim done for her Bday.
Quick point different design but same problem in my neighbors house.
Had to install normally closed solenoid valves at zone pumps.
With out totaly getting into it I would split the systems use the tankless for the domestic & get a boiler for the heating.
I'll get more into it sunday night when I might have time.
Maybe Rob can jump on this one.Do you look to the government for an entitlement, or to GOD for empowerment. BDW
With out totaly getting into it I would split the systems use the tankless for the domestic & get a boiler for the heating.
That is the fallback position, and i'm comfortable doing that work myself. I'd like to save her the money if this tankless can do the job, though.
Thought to enlarge these for clarity in the smaller details.
'Nemo me impune lacesset'No one will provoke me with impunity
I have radiant on the second floor of my house, baseboard on the 1st. Both and the hot water are supplied by tankless TRIANCO direct vent natural gas unit. The plumber installed a sensor on the outside of the house in order to provide more efficient responce to the system.
Up to this point it has worked fine. Other than the outside sensor, I'd ask how thick is the flooring to which the tubing is stapled? That too may be part of the reason that it is cooler on the upper floor.
At some point I'd like to upgrade to RFH on the 1st floor and upgrade the unit to something that will be more easily serviced.
Good luck, let me know if any of this helps.
KaiserRoo