plugged boiler

saber

I have a Weil-Meclain gv gold series 5 boiler, Lp fired. It is almost 15 years old and i installed it new in a old farm house with cast iron radiators. The last 6 to7 years i have had a problem with air flow and the boiler cycling on and off. My problem has turned out to be a plugged combustion chamber. I have had to vaccum it out almost every year. The unit is creating alot of condensation and rust and plugging. Any ideas on what my problem might be.

Mark Eatherton

Hold the boiler up to the camera so we can see it :-)

The Gold boiler is a "NEAR condensing boiler". It has a thermostatic valve, similar to the ones used in automobiles, that keeps the boiler block above the dew point. If it has been removed, or has failed in the open position, your boiler IS a condensing boiler, and it wasn't meant to be. THe older GV's actually had an internal pump to keep the block consistently warm. If it fails, then again, you could be exposing the block to condensing situations. It is virtually impossible to tell if this pump has failed, because it draws the same amount of amperage with a lock rotor condition as it does if it is working, and it is NOT an easy pump to replace.



Replace the internal thermostat and the internal pump. Or, replace the boiler with a true condensing appliance and be done with it. High mass systems and condensing boilers are a perfect match for comfort and efficiency.



ME

icesailor

Condensing 15 YO GV:

Mark et/al:

That boiler has an internal thermostat. There is a old W/M tech bulletin on it. The company that made the thermostat is no longer. The only fix is to remove it. Not easy. When you take the top off, you will see a painted black fitting with a 1 1/4" black plug. You must remove this plug and remove the thermostat. When you get it out, there is a hole in the bottom of the fitting. You must plug this hole with a copper cap, driven into the fitting. It is one of two sizes, 1/2" copper or 3/8" copper. You won't know until you get it apart.

Getting the plug out can be done if you have access to a large 8 pt socket with a short extension and a long breaker bar. You may need a breaker bar on the socket. You need to back up the fitting or you may twist the assembly and cause a real problem. You will need at least a 2' pipe wrench or two.

If you don't have a 8 Pt. socket, you can make/use a recessed plug that fits the square plug on the thermostat. It may be 1". I took a 1 1/4" blind plug, screwed it into a 1 1/4" steel coupling with a threaded pipe. I brass brazed the plug to the coupling  to the pipe to the coupling, making an assembly. Then, I could get a pipe wrench on the plug way above the boiler. I do this getting blind plugs out of floor clean outs. Once you remove the thermostat and plug the hole, the boiler will work fine.

You just answered a question for me though. I have a boiler that just had this done. I didn't know that there was a problem and the customer called the LP gas supplier who does service. The guy knew immediately, what was wrong. He did the repair last June. I drained the house last Thursday and when walking by the exhaust, I noticed all these rust in the bottom of the outside exhaust termination. They were like coffee grounds. I knew where they came from but not why. Now, I know why. It was caused by the bad thermostat. It was probably bad for years. It may have worked for years when the house was used year around. But when I started to drain it for the winter about three years ago, the thing broke.

Mystery solved.

Look for that tech bulletin. 

saber

Thanks

Thanks for the help. Where can i find the tech bulletin? I was thinking they were calling this valve a mixing valve in the manual, I will check this out when i get home. I have been a coal fired power plant mechanic for 26 years so i know some about pipe and boilers but on a much larger scale and some of the terms are not the same. I have found this project to be alot finer details and much more difficult to heat water and get it moving at home. When our boiler gets plugged at work they actually use dynamite to clean it. Thanks again, i can use all the help and comments available.

Mark Eatherton

I had a friend who use to use dynamite on clinkers the size of railroad cars....

I'm certain he'd be glad to use dynamite on your boiler, provided it is not inside your house :-)



If I were you, I'd eliminate the internal thermostatic bypass and install an external thermostatic bypass



http://www.danfoss.com/North_America/Products/Categories/Group/HE-HEC/ESBE-Mixing-Valves/ESBE-Thermostatic-Valves/bdab43d8-e48d-4370-92b3-1205d8f7c6b9.html



Or, as I said, if budget allows, get rid of the Wiley Mac completely and install the condensing appliance of your choice. AND reduce your fuel bill a minimum of 30%...



It also allows you to eliminate the extra pump if you do it right.





ME

icesailor

Plugged Boiler:

When you take the top off, and you are standing in the front of the boiler with the piping on your left, it is the painted black thing on the top left with a plug in it. It's an easy fix if you get the plug out. And they all work fine if you plug the hole as W/M tells you to.

If you can afford to, change the boiler. If you are tight on cash or have other things you want to spend your cash on, fix the boiler. They work pretty well. They do have some other issues but you are not describing them. If you can fix it yourself, it may cost you under $25,00. A new boiler, Mucho Dinero.

tim smith

The boiler also probably needs tear down and descaling

This is not an easy task, takes most of the day and 3 - 5 of their gasket kits which are not cheap. Tear apart boiler completely, separate section. Descale all the scale inside. Put back together with new gasket sets. Put in conversion kit for thermostatic bypass and change the igniter if it is more than say 3 yrs old. Pretty involved but will put it back in good operation. Or, change boiler to a good condensing boiler.  Good luck, Tim

saber

found thermostat

Thanks again for the help. I have identified the thermostat which they do call a mixing valve in my manual. This will be a spring job if i can get by. It has been very cold in Indiana. It seems to be operating fine for now, well most of the time. Im going to check into the gasket kits availability to me and plan a compete rebuild this summer. Im going to make another post concerning my piping system. Thanks again!

Charlie from wmass

Save your blood pressure and

money. Get a new boiler in the spring. if this has been condensing for years it is pretty rotten inside by now. To descale this and replace the gaskets is like putting a rebuilt engine in a million mile New York City taxi cab. Sure it will be tight in side but lots of other things to go wrong. The cost of the parts will out weight the cost of a boiler. I am not talking of plugging the thermostatic valve I am talking about cleaning up the rest of the mess it has caused.