Single handle shower with tankless water heater.
mpergiel
| Posted in Energy, Heating & Insulation on
It seems like the pressure/flow drop through the tankless water heater is causing too much cold water to mix in at the single handle shower faucet. I checked the fill rate on hot and cold at a sink and got about 5-10% difference. Before I change to a 2 handle faucet are there any considerations?
Temp and pressure sensitive valves seem like a overthought solution. Pricey too, if that were an object.
Replies
So you have no regulation of the hot in the current valve?
It is not hot enough. Like I said, I suspect the pressure drop through the taknless heater is biasing the flow through the valve. But thanks for answering.
Is the shower faucet brand new? Is the problem new? Did it ever work correctly? The single handle faucets have mixing valves to control the hot and cold mix. Sometimes they get cruded up and don't work correctly. What is the shower faucet brand? Some are easily cleaned or the part(s) replaced.
Everythign is brand new, including all water lines. Plenty of plenty hot water comes out at the sink, which has separate valves. Seems like this would be a well understood problem among diy plumbers.
What is also possible is that when you turn the temperature down at the valve, you reduce the flow through the heater enough so it shuts off. Make sure you are getting full flow through the valve. Try it with the shower head off.
The shower head makes no difference. the flow is already restricted on the hot side through the heater.
That's not the point. A tankless heater depends on a minimum flow to turn on. If you reduce the flow below the minimum the heater shuts off.
Did it ever work correctly?
These have anti-scald screws which prevent the faucet handle from being turned too far to prevent possible scalding. These screws are adjustable by you.
Another reason would be a stuck mixing valve within the unit.....but if it's new this probably isn't it as this occurs over time with mineral buildups from the water.
If you have comparable hot and cold flow at sinks with 2 faucets I don't see how the tank would send different flow rates to the single handle faucet.