I have a Weil MClain EG75PI boiler (2 pipe radiators) and have been having heating issues the past few days. I beleive the boiler to be a 1988 vintage. This is in a 3,000 sf residential application. On the 1st floor appoximately 50 percent of a radiators leaves heat, the balance remain cool. On the second floor approximately 25 percent of the leaves heat. This is on all radiators. With the thermostat at 65, we maintain approximately 70 degress in the basement, 60 degrees on the first floor, 50 degrees on the second.

The boiler fires and runs for approximately 1 minute before shutting down. It does have an intermittent option but burned longer in previous seasons. The pressure gauge typically reads 2 psi. From time to time, the boiler does not fire, only hearing the clicking of the ignitor. When this occurs, the gauge reads 10 psi. Once the pressure drops, the boiler fires and the radiators partially heat. I have not attempted to raise the thermostat to correct the problem as I assume this only burns fuel with no appreciable outcome. I remove sediment monthly (during season) and the water level is correct.


I know little about boilers but am very mechanical. Before you say call a professional, I would have to ask if there are any in my area. I have called several, and between missed appointments and "oh, this is steam" I have been several days now. I am running out of vendor options no longer have patience for them.

Thank you in advance for your help.

 

That 10 PSI is a part of the problem, I'm sure... possibly the siphon tube is plugged up with 'crud'... just a guess.

The steam heads will be along shortly I'm sure. I put STEAM in your title to attract them.

 

Dan Holohan has several books which may be of intrest to you. He is THE guru of steam systems. My steam experience is very limited especially with 2 pipers.

 

@NJ Trooper - Thanks for changing the title and the siphon tube idea. I'll check that tomorrow evening.

@Grady - Thanks for the authors name, I'll check the library.

 

Okay, I've taken the day off work in hopes of correcting the problem.

Unfortunately, my local library does not have any DIY books on the matter. I'll buy some for later problems, but no value today.

I've timed the burn and it is between 30 and 45 seconds. This does not appear long enough to me.

I have removed/reintalled and validated the low water level float and switch.

I have removed, cleaned and reinstalled the siphon tube. It had rust deposits and some slime but was not blocked.

I don't want to just throw parts at it, but I am trying to use a bit of logic. I am off to purchase and install a steam pressure limiting valve. Would my next step be the intremittent electronic ignition system if the limiting valve does not correct the problem? Thanks again for the assistance.

 

Not being a steam head, I'm completely clueless as to what you mean.

I'm glad you don't want to be a 'tinker'tician ! Do you own a multimeter and know how to use it?

Also, I must repeat my 'mantra'.... "Never trust a boiler gauge.... Never trust a boiler gauge... never trust a boiler gauge... z z z z z "

Replace it.

I don't recall and too lazy to read back... does your boiler have standing pilot, or spark ignition?

 

It appears that your boiler may have a 'millivolt' gas valve. The 'control supplement' here (for standing pilot models):

http://www.weil-mclain.com/en/multim...standpilot.pdf

Indicates that the EG75 has a thermoPILE and a 'dual limit' control.

 

If your boiler has a spark ignition, your problem may be as simple as cleaning the flame sensor rod. See control supplement for spark ignition here:

http://www.weil-mclain.com/en/multim...supplement.pdf

 

Please note also that all of these systems have "FLAME ROLLOUT" and "SPILL" switches, and you could have something going on that is causing them to trip out.

 

NJ Trooper - Thanks for the manual sup., I had downloaded the installation manual earlier in the week. Yes, I have and can use a multimeter.

I now have normal heat and I don't really know what the culprit was, but I learned volumes today. I removed, inspected and cleaned most control items, ran new wires to the thermostat and replaced the thermostat.

I learned so much about the controls and boiler itself, perhaps I'll learn the rest of the system as time goes by. Thanks again for all of your help and Merry Christmas.

 

I'll add that while I really dont' know if the problem was a single item or combination, I've spent less than $50 and it was very satisfying.

 

I will tentatively say GREAT! in hope that the problem doesn't return. If it does, let us know and we'll help ya track down the culprit.