Laars tankles water heater
polarbearoption| Posted inMechanicalson
I was at my in-laws summer house over the weekend and went into the mechanical room. I was surprised by how warm the room was. They have a Laars Mascot tankless condensing boiler for hot water and radiant heat.
There was no water being used and the radiant system was not calling for heat.
Since this is an on demand system, I figured it would not give off much, if any, heat since the house had been vacant for at least a week.
Does anyone know if this is “normal” or if something may need to be looked at? And if it is normal, it would seem that it would not offer the savings I might have expected.
Thanks for any help.
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Replies
Kevin,
Some "tankless" water heaters have a small buffer tank that is constantly kept warm. Some gas-fired tankless heaters have a pilot light.
Other than that -- I'm not sure what the source of the heat would be. Your instinct that something is wrong makes sense.
I don't think the Laars has a buffer tank or a pilot light, but that boiler does contain some water, maybe 1/2 to a couple gallons.
The traditional (and wasteful) way to control a heating boiler is by setting a boiler temperature. Traditionally 160F to 200F. The contractor walks away and the boiler itself is ALWAYS at 160F+, and only gives up its heat to the house when the circulator pump kicks on. The house thermostat(s)only controls the zone valves which in turn kick on the pump.
Yes, a warm boiler room in a summer house means bad control logic or settings. That boiler has built in controls that would eliminate the problems. As a first step, it should turn the boiler completely off when it is over 55F- 60F outside. It should also go up to 160F+ only when it is really cold outside.
Of course, for DHW, the boiler is fired automatically when it senses water flow as demanded by the fixtures.
I see this sort of trouble all the time, the contractors set up systems for zero callbacks instead of energy savings.