ending waterlogged steam system

patrick linhardt

Hi John,

Heat-Timer or tekmar are both good cycle rate controls. In other words, they turn the boiler off and on in response to outdoor temperatures, longer run cycles for colder days and shorter run cycles for milder days. I take it that you must be running the boiler off the pressure control. That will have a tendancy to overheat the building if there is no feedback, like a themostat, even if you have TRVs.

I would recommend installing a pressure control that can keep the boiler under 2#, there is no reason to go above that. I would also recommend the cycle rate control for better comfort, but maybe more importantly, better efficiency.

What exactly is the water problem? It will probably go away with lower operating pressure and the boiler cycling on and off, but please describe in more detail.

Best regards, Pat

johnny4

ending waterlogged steam system

We have an old institutional building (about 20,000 sf) with one-pipe steam. We replaced the boilers 1 1/2 years ago, but the system still overheats (with TRVs in place) and one controls expert says we need to put in a Heat Timer-type control to turn the boiler off to let condensate return. This new boiler (Weil-McLain) is also operating at 3+ psi, whereas the old boiler operated at 1-1.5 psi. The factory-installed pressure control only goes down to the 3 psi setting.

Questions - (1) are there other pressure regulators that can be installed to lower the pressure in the system - safely, and (2) what has been readers experience with Heat Timer type controls?

Any feedback from you guys is much appreciated.

Unknown

John

Totally unrelated to the brand of boiler, but do these One-Pipe TRV's have Vacuum Breakers installed on them? They are needed in order to allow condensate to return either after the cycle has completed or the TRV has been satisfied. Without them condensate will be held in the radiators until they open again. Look up the brand of TRV you have and you will undoubtedly find these as a neccessity for one-pipe applications. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

johnny4

thanks, will get more info

I will check for vacuum breakers on the TRVs. Nice point. We're also pretty sure we need to alter the pressure control, assuming we can find one that will substitute, and a colleague is researching that.

J.C.A._3

One more thing to look at.....

Are the returns of the "new boiler" lower/higher than the returns of the old system? Did you miss any "one way valves"(swing type) that may have been installed on the returns ?

I ran into a nightmare a few years back where the steam traps were being fed from 2 sides....and that don't let steam or condensate, flow like it should. The solution came from a diagram I found in a Peerless manual describing a "false waterline",being built into the system.

Steam TRV's will work when the system is designed properly. I'm sure you can find some Vaporstats sitting in a suppliers warehouse somewhere. Lord knows they have been sent back so many times because the guys installing them didn't understand why they were there in the first place.(pressure IS GOOD !!!.....WRONG!!!!)
JMHO. Chris