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Burnham Revolution not keeping up

AOldeman Member Posts: 2
Burnham RV4N gas boiler is operating but I am not pulling full hot water supply temperature to the house. House temps got to low 60s during the day and mid 50s at night ... burrrr!

- Direct vent install, internal Taco circ pump controlled by VS3000 ... appears to be working.
- Just had aquastat replaced about 4 wks ago (btw, this boiler uses a proprietary L8148). Set at 210'F.
- Secondary pump is Grundfos Star S 21 FX, 3-spd pump (house is 1875 w/converted steam distribution).
- Very cold outside last 2 days (0'F +/-) so possible poorly/uninsulated house is just too much but I doubt it.
- Burner fan is running continuously, and burner flame is cutting out periodically (as if it makes temp, shuts off and then maybe kicks on again before burner fan can shut off?)

The issue I see is that I'm not pulling high enough HWS temperature out of the boiler and yet the boiler thinks it's making temperature because the burner is shutting off.
- I think the secondary pump is working okay because when I change the speed I can feel the HWS temp to the house changing.
- I've disconnected the Domestic HW circulator from the switching relay to remove that load and dedicate it to the house.

Not sure what else it could be. Any help appreciated.


  • vvzz
    vvzz Member Posts: 39
    Not a paid 'professional', but maybe not enough radiation? It being a converted steam system makes that even more likely.
  • Ironman
    Ironman Member Posts: 6,579
    You've omitted two crucial things in your description: the btu rating of the boiler and the heat loss for the house. Was a detailed heat loss calculation done when the boiler was installed and the system converted from steam?

    The other thing would have been a radiation (emitter survey) which, as vvzz mentioned, would have determined whether your present radiation would have emitted enough btus to heat the house at design temp using hot water.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • AOldeman
    AOldeman Member Posts: 2
    84 MBH Output and the house is about 2,200sf. Don't have a good idea of radiation output but it is the original steam radiation.

    You bring up valid points and I did wonder about capacity versus load, but I recall that last year it performed pretty well on some days that got down into the single digits. Just wondering if there is anything in the control of the boiler that might present with this kind of issue. Didn't make sense that the HWS was not what it could be while the burner was cycling off.
  • Tim McElwain
    Tim McElwain Member Posts: 4,481
    What does the gauge say the temperature is when it shuts off? There were some problems with L8148E relays from Burnham for that boiler. Does it have the plug for a vent damper? Is a vent damper connected?
  • Jason_13
    Jason_13 Member Posts: 299
    edited February 2016
    There is no vent damper on Revolutions as they are induced sidewall vented boilers.
    Is the bottom light on the VS3000 blinking all the time including when the boiler shuts down. The on board pump should be at 100% around 165f.
    Try moving the wire from terminal #3 to terminal #1 on the VS-3000 as a temporary test. Make sure to turn the boiler switch off first. If problem resolves the sensor is off the supply pipe.