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Weil Mclain boiler replacement
Weld_fix
Member Posts: 14
Hello, I'll just state right out of the gate that I'm a do it yourselfer. We have baseboard heat in our home and our boiler crapped out at the end of last winter. I've been weighing replacement options and after getting a quote for around $ to have a pro do it I'm leaning towards doing the swap myself. We currently have a 105k btu Weil Mclain GV-4 series #1 and I'm thinking of replacing it with a Weil Mclain GV90+4. After reading the entire installation manual it looks like it's more or less a direct replacement? In other words I should be able to take the old one out and connect the new one to the existing piping, unless I'm missing something? I do want to pour a small cement pad to put the new one on to get it up off the floor a bit and add an air eliminator to the system which we don't curently have. Any words of advice or caution would be greatly appreciated, am I on the right track?
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Comments
Do you have a manometer and a combustion analyzer?
Once you get whatever you decide to put in installed, you will have to tune it up -- and for that you will need a manometer or sensitive pressure gauge and a combustion analyser -- and know how to use them.
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
Can you post pics of the existing?
Is the existing piped primary/secondary, as it should?
Are you up to date with you're codes? BFP, LWCO, etc. ?
You're only worth $? Family?
Your not patching drywall or adjusting the rear slider. Both of which are on my list, but somehow I'm sitting on the patio on a lazy Sunday afternoon
Of course there's always the option of fixing my current boiler, for the last few weeks of the previous heating season it would only run with the vent cover removed from the outside of the house. In other words with the exhaust pipe exiting straight out the house uninhibited by anything even slightly restricting exhaust flow...
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
Police & Fire Equipment Lead Mechanic, NW WI
Lover of Old Homes & Gravity Hot Water Systems
>
> Why do you guess my current system will not meet the criteria to be piped in/out on a GV 90?
Well, because @Ichmb wasn't guessing. It's in the manual you read completely. (See diagrams)
Even if you have zone valves and using only the internal system circulator, primary/secondary is preferred to most in the trade. Especially when the manufacturers literature shows it.
These guys are here to help, not hinder, so just because you dont agree with the advice and recommendations given, they're given in the interest of safety first.
Call 402-340-5314 or PM me.
I am in northern NE, just considered a short trip in the Midwest for us......only 1 1/2 states away.
The GV90+ is a condensing boiler if I remember right, which means you will also have to change the exhaust system, and have a place for the condensate to go.
Also, the exhaust gasket is cracked which doesn't surprise me. This is why I don't like gaskets in an exhaust system. I have seen too many like this. Say what you want to about PVC, but the joints don't leak over time. At least none I have ever come across.
Also, like you, I do all my own work, but know when to bring in the right help when needed. In my area there are no permits for anything, as there are no inspectors. ( except in the city limits themselves.) But what you have to think about is if and when it comes time to sell your house, are the next people going to be buying something that is done right. Again I do not know your skill level, just saying.
Rick
> Looks like you need to go a lot deeper into this if there is that much scale in the elbow.I believe it will require some serious cleaning inside.
> The GV90+ is a condensing boiler if I remember right, which means you will also have to change the exhaust system, and have a place for the condensate to go.
> Also, the exhaust gasket is cracked which doesn't surprise me. This is why I don't like gaskets in an exhaust system. I have seen too many like this. Say what you want to about PVC, but the joints don't leak over time. At least none I have ever come across.
> Also, like you, I do all my own work, but know when to bring in the right help when needed. In my area there are no permits for anything, as there are no inspectors. ( except in the city limits themselves.) But what you have to think about is if and when it comes time to sell your house, are the next people going to be buying something that is done right. Again I do not know your skill level, just saying.
> Rick
The series 4 I will be installing uses a T off the boiler with a drain on the bottom of that. I will running all new exhaust when I install it.
A drain tube with loop trap was attached.
This collects a fair amount of condensate.
That WM is a "nearly" condensing boiler.
The internal thermostatic mixing valve usually fails and you end up with too cold of water return thru the CI exchanger.
Probably happen to your old one and also on your "new" one.
Series 3 & 4 had the problem corrected with a bypass circulator instead of a mixing valve.
You should get and read the I&O manual for the series 4.
Your pictures of the discharge elbow full of rust indicates you may have had the internal mixing valve fail and allowed cool water to return into the boiler.
Rick
> Is it just the way the solder looks, or did the return line ball valve shift during soldering? It looks like it is not in the same place it started when it was first soldered, and is only half on. You might want to check it out.
> Rick
Yeah no it's all the way on, that's just a sloppy soldering job hahaha. I'm picky about that stuff but was offered help that day and didn't want to refuse it seeing as how it was 10° outside the day I switched over and I wanted to make it happen as fast as possible. So some of them aren't the prettiest but none of them leaked
Why not leave the boiler unmodified and just use the Grundfos as a secondary pump? Just a couple tee's and a bit of 120v wiring would do the trick.
The first series 1 & 2 had an internal mixing valve that had a high rate of failure....this may have produced the iron rust in the exhaust elbow of your first boiler. It was starting in my old one.
> What does the series 4 boiler have for condensation protection from low return water temps.
> The first series 1 & 2 had an internal mixing valve that had a high rate of failure....this may have produced the iron rust in the exhaust elbow of your first boiler. It was starting in my old one.
The series 4 has two internal pumps, a primary and a secondary. The secondary pump mixes return water to reduce condensation. If I remember right they claim it can handle return water temps as low as 60°.
> Well it's in finally. I went from a GV 4 series 1 to a series 4. I also switched it over from a closed style expansion tank to a bladder style and also added a Spirovent, auto fill valve and backflow preventer which my original system lacked. I verified incoming gas pressure at 10.5 inches of water column. I purchased a new starter tee and gasket as the one that came with it was pretty rotten, instead of buying that overpriced stainless vent pipe I fabbed up my own out of 3" 304 stainless tube. It's in two pieces, connected with a triclover fitting in the middle. When I first fired it the baseboards didn't seem to be getting as warm as they used too so I switched the main circulator pump from the Taco 007-F5 that came on it with a Grundfos UP15-42F off my old boiler. That made a huge difference. As far as I can tell everything is working as it should, let me know what you guys think.
>
> Glad, it works for you. Seems like a bit of odd approach to replace the internal pump with a bigger one, and not consider a P/S arrangement.
> Why not leave the boiler unmodified and just use the Grundfos as a secondary pump? Just a couple tee's and a bit of 120v wiring would do the trick.
I'm sure that would have been a better way to go, I'm not a heating expert (obviously lol) so I just did what made sense to me at the time. Plus I was trying to keep as much of the original piping as possible intact just to keep things simple.
> I did not read all the post but I will just say IMO those boilers are junk. Get any boiler but that one.
You may be right, all I can say is the one I just pulled out ran for over twenty years. Not sure what the typical life span of a boiler is...