Lukewarm Water

[edwardjk]

An extension of my home is heated by a high-mass radiant heat system. The heat source is a heat exchanger mounted on top of one of two 35 gallon water heaters. That water heater also provides hot water to the master bath.

The problem is the water is lukewarm on cold winter days. I turned up the thermostat on the hot water heater but see no improvement.

Any ideas to get hotter water?

[hvac hero]

are the water heaters "quick recovery" ? There are a lot of houses around here that have the aqua systems in with the quick recovery water heaters. I've seen a few occasions where a plumber will replace it with a standard water heater. Of course he always does it in the summer & its no big deal. In winter though, the people have to turn their heat off a hour before they take a shower to have hot water.

[edwardjk]

They are Bradford White Powered Direct-vent water heaters. How can I tell if they are "quick recovery"?

[matt8085]

Does the system have triple acting aquastat? This would give priority to domestic hot water over heat.