I installed a Bosch Tankless water heater yesterday and replumbed my house.
Everything was groovy until I went to test the water, it’s not hot. I set the temp. to 140 to see if it would warm up and nothing, I checked the digital display and it’s blinking a trouble code A9.
I went through the guide and tried their fixes for the code and still no hot water. Just luke warm, barely enough to take a shower.
Any plumbers deal with these? What the problem is?
Listeners write in about earning trade-work merit badges and ask questions about radiant cooling, indoor air quality, and radon-control systems.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
just a guess,is your supply too warm to trigger the unit on?
THats not it, I checked that. It starts up when a hot water faucet is turned on. THe temp flashes on the display (says its supposed to do that) then after a minute or so the trouble code pops up and the water cools off. Weird.
What is the A9 code for?
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Q. A9
Hot water temperature sensor not sensing correct selected temperature. This error code may flash on display while heater continues to run or it may shut off the heater requiring resetting of the error code.
A. 1. Check that the temperature sensor is firmly connected to the hot water pipe. The sensor should be connected to the middle of the horizontal section of the hot water pipe.
2. Heater not able to hit selected temperature due to high inlet water temperatures at low flow rates. Verify the heater is being fed cold water only. Do not feed preheated water to this unit. Increase flow rates whenever possible. Check for obstructions and make sure all outlets (i.e. showerheads, faucet aerators and whole house filters) are clear of debris. Also, the heater's inlet filter screen should be inspected and cleaned. Cold water inlet screen dirty. See: TWH G2-02 Service Bulletin.
3. Blocked or improper venting. Failure to vent in accordance with the specifications in the installation manual or an obstruction in the vent path may cause improper combustion, inhibiting the heater's ability to reach selected temperature. Also, verify back draft flapper inside flue gas collector collar opens and closes.
4. Low gas pressure inhibiting the unit from reaching selected temperature. The sensor is not reading expected temperatures. Ensure gas pressure is in accordance with specifications in the installation manual. A gas pressure reading is needed to proceed further. Contact your original installer or a local certified gas technician to obtain this reading. TWH G2-03 Checking gas pressure.
5. Supply voltage too low. If voltage to the unit is low, the fan may not achieve the appropriate speed for proper combustion to reach selected temperature. Verify electrical power supply is a properly grounded 120V AC 60Hz circuit.
6. Defective control unit. Control unit may not be accepting signal from temperature sensor. Call Technical Support (800) 642-3111for further instructions. .
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I looked that up on their website, I have checked all but one of them and I am going to do that now. Check if the venting is working.
It's just an elbow and a 10" piece of stainless steel for a vent. I don't see how that could be clogged. It might be in the unit itself.
I may have gotten a defective one.
You said the water get's hot for a sink faucet. If the temperature at the sink is correct (120-140 setting), try reducing the flow rate at the shower.
One of the answers from the trouble code is "not reaching expected temperature" which would occur if the flow rate is higher than the heater spec.
I'll give it a shot, I installed new ball valves on the new plumbing so I could shut stuff off, I may as well use it.
Fricken computers man, they aggravate me. If I put a regular powervent in this would not be an issue.
My Bosch it 6 years old and still working great! Don't despair yet, you will love the non-stop hot water!
When it was first installed, my daughter said "there's still hot water!" This was after her brother had just showered, he would normally stay in the shower till the hot ran out! I often had to "kick him" to leave some hot for others.
I am beginning to think my gas supply line is too small. Hard to believe, I installed a 25' length of CSST T'd off the main trunk line.
I am still messing with it.
Your report is good to hear, I may have to call in some help on this one.
IT"S ALIVE!!!!!!!!!!!!!!!
It seems that the temp sensor in the unit that clamps onto the water line was loose.
I kept looking through the unit looking for something and there it was, hooked it up and I took a kick azz shower.
Thanks for the replies. I have been working on the plumbing and hot water heater for 4 days, I started to get frustrated with it. All be good now.