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Hot water help

We recently converted our heating from Oil to Gas. We already had a gas line for everything except the Heating, now even that's gas based. During the conversion, we got the following:

Burnham Independence IN5 Steam Boiler

AO Smith XCVX-50 High recovery 50 Gallon Water tank Hot water Heater (our old GE water heater had runs its course and looked like it was about to go)

Everything works well. Seems they are feeding the main water (cold) line to the steam boiler and there is a LWCO and manual reset/automatic water feed installed. Everything works great (knock on wood).

My concern is that whenever the boiler is running, the hot water is way too hot in our pipes requiring excess mixing with the cold water during shower. However, when the boiler is off (during summer time), the water level is normal.

What is the cause of this. There doesn't seem to be any interconnect where the Boiler provides the hot water (indirectly), so where is this excess hot water coming from.

This bothered me even when our boiler was oil fired. However, at that point the piping was so complex (and borked, which prompted an upgrade to gas heat), that we didn't know what was what. Partly because the water feed wasn't working. Now, the gas fired boiler's piping is way simpler and straight forward.

Hope someone can help me understand what causes this hot water to be too hot during boiler cycles.




  • Zman
    Zman Member Posts: 7,572

    You are certain that you do not have a tankless coil on the boiler that preheats the hot water? That would explain the problem?

    What temp is the water heater set?

    I assume you do not have a thermostatic mixing valve? That would fix it.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • cchhat01
    cchhat01 Member Posts: 17
    edited November 2013
    Fairly certain

    As far as I can tell from the piping, the water line is split into several outputs, one of them going to the boiler, the other to hot water heater and several others to the various cold water ends of the faucets in the bathroom/kitchen sinks, etc.

    The water line coming out of the hot water heater is being fed into the home's various sinks, bathroom showers, etc. I don't see any connection between the hot water from the heater and the boiler's hot water. There might have been something when we had the previous oil fired boiler, however the piping has no interconnect.

    The water temp is set a tad below normal setting which should be just below the 117-120F range. You are correct about the thermostatic mixing valve, but since there is no mixing between the boiler's hot water and the hot water from the ao smith water heater, it doesn't make sense to me.

    What am I missing?

  • kcopp
    kcopp Member Posts: 4,440
    I think....

    you are going to need to post some Pix. You say a steam boiler but I am thinking its a hot water boiler w/ a coil.
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