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Dear sirs—my question concerns excessive vacuum in my new 1,050,000 btu peerless 211A steam boiler feeding a one pipe system. When the burner shuts off either by thermostat or by vaporstat , within about 10 seconds the waterlevel in the sight glass drops quickly from the half-way point to below the low water cutoff level. When it slowly returns in 5 minutes or so and the burner starts then all the rest of the water comes back as quickly as it had disappeared. I have a gate valve , and a check valve[ said by peerless not to be needed]
on the return just before the Hartford loop and this double phenomenon takes place even with the gate valve closed!!
Since noticing this we have corrected mis- sloping dry returns and ,replaced plugged main air vents and ,missing pipe insulation , but still have the problem.
This vacuum must act on the main steam piping [or inside the boiler itself] which is installed exactly per the peerless instructions. Both the installer and I are mystified by this MYSTERIOUS MIGRATION of WATER .
If I knew where the vacuum formed I could find a way to relieve it but I have not been able to detect it on the main gauge ,or the main steam line gauge or on a gauge installed on the steam riser.
As it only takes 6 gallons of water to bring the water level up from lwco cutoff to mid point we are not seeing big volumes of water being moved around.
Has anyone else noticed this effect on other peerless boilers?--nicholas


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  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576

    happy new year!!
    thanks to noel's advice i now have removed the improper "menora" arrangement of stepping down dry returns on my peerless 211-a 1050000 btu one pipe system and installed straight down piping on all 6 returns.
    the problem was that as the boiler pressure forced the return waterlevel up these horizontal steps would hold lots of water.
    i now have the problem in cold weather of slow returning condensate even though it all comes back in 20 minutes or so. as i do not have a codensate pump i wonder if i could use air pressure on a tank in the returns to force water out of the tank when called for by the lwco therefore making more water available to the boiler when needed.when the thermostat is satisfied some sort of valve could open and release the air pressure allowing water back in the tank.
    i have been planning to put this boiler on a backup battery ups system as electricity in our innercity area has been subject to interruptions lately for a couple of hours or more.the air compressor i found is less than 2 amps draw.all the pumps i have seen are more power hungry than that and the tank is already in my return--a 5 in manifold that had been the base of the "menora"
    any thoughts??
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