Real Estate Investor · Point Pleasant Beach, NJ · Member since 2014 · 103 posts · 52 votes
Hi BP!
I have a hot water gas boiler heating system that causes me problems every winter. About once a month I get a phone call that the heat isn't working correctly, not reaching the desired temperature. My solution so far is to:
1. Drive out to the property
2. Purge the return water line to the boiler until all the air bubbles and pockets are out
3. Fire up the boiler and make sure the pressure and temperatures are correct
This always works, however it is a temporary solution. Because the next month I'm back doing the same thing. I've talked with plumbers who say that the air in the system is the problem and what I'm doing is correct. But there has to be a more permanent solution, has anybody experienced this before?
There is an expansion tank and it appears to be hooked up correctly. The whole system was brand new in 2010. Is it possible that the tank needs to be replaced entirely?
Any specific things to look for around the expansion tank?
Assett Retrieval Specialist · Rowley, IA · Member since 2014 · 31 posts · 6 votes
11y
Most codes require an auto bleeder to allow air to escape from the system. This should be a device installed at a high point in the hot water loop. These bleeders are known to fail periodically and may need to be replaced. I would also be questioning why you need to bleed air so often. This is an indication of a possible leak. It is a closed loop system, so once the air is purged from the system, there should be no problems. If there is a leak air will continue to be introduced into the system via the fresh make up water valve, or from the leak itself once the water has drained enough. If your taking in water, your also leaking water somewhere. Another problem you could end up with is, by introducing alot of fresh water the system could become contaminated if your boiler water is treated. Mixing treated water with fresh can create too much bacteria growth and cause system falure. A quick way to make an initial guess is to take a small sample (a small coffee cup) and smell it. If it has a bad odor, it is probably contaminated.
Joe makes a good point on the expansion tank as well. If you give it a couple taps on the side it should sound empty, or have a ring to it. If it sounds full, it's saturated and needs to be replaced.
Let's hope it's as simple as changing the bleeder or expansion tank. That should be fairly inexpensive. I would not recommend using the plumber you spoke with because if he would have simply bled the system and left it, he would not be providing complete service.
This is really helpful! I'm not sure if my system has an auto bleeder but I'll definitely check on this next time I'm at the property. Like you said, hopefully it is a relatively simple and inexpensive fix.
I'll keep you posted next week when I take a look.
Speak of the devil, my tenant just called me about the heat not working! Looks like I'll be going there today after I get out of work. I'll inspect the bleeder and the expansion tank and take some pictures. I'll post them tonight or tomorrow.
I sincerely appreciate your tips, I'm desperate for a permanent solution.
Commercial Real Estate Broker · Denver, CO · Member since 2014 · 6 posts · 3 votes
11y
All of these guys have made good points. Are you going to the highest point and bleeding from there? Are the complaints coming from the same units? If there are not bleeders valves along the loop, you may need to add some.
Real Estate Investor · Buy & Hold Investor from Seacoast, NH · Member since 2013 · 63 posts · 15 votes
11y
Do you have an air separator with auto vent installed? I recommend Spirovent.
@Roy N. also has a good point. Though I think that the air might be coming out of the make-up water that you add every month when you do your purge. The air bubbles come out of the make-up water that you add and end up in larger pockets.
Do you have an air separator with auto vent installed? I recommend Spirovent.
@Roy N. also has a good point. Though I think that the air might be coming out of the make-up water that you add every month when you do your purge. The air bubbles come out of the make-up water that you add and end up in larger pockets.
Perhaps ... but it takes a fair amount of make-up water to get air-locked ... if he is adding that much water, at least the leak should be easier to find ;-)
Did another purge today just to get it working for now. Inspected the system and checked expansion tank, bleeders, valves, etc. I found 2 leaks coming from valves. One of the values is on a supply pipe going up to heat the apartment. The other valve was on a pipe that was from the hot water heater tank going into the boiler. I'm thinking the solution is just to replace both valves? Both were compression fitted.
The expansion tank seemed fine and I didn't see anything else unusual. Would it still benefit me to install an air separator such as a "Spirovent?" Here are some pictures to help illustrate:
Refer to the red ovals I drew - the valve with the green handle has a slow leak (right side of pic). There is another similar valve upper left above the hot water tank that also has a slow leak, but the lighting was poor so you can't see it:
Closeup of the leak:
Closeup of the other leak (this is the valve above the hot water tank that you couldn't see in pic 1):
Also noticed this corrosion on a completely different section. It wasn't leaking at all, but it looks like it used to. Does this valve also need to be replaced?:
Rental Property Investor · Fredericton, New Brunswick · Member since 2013 · 7k+ posts · 4k+ votes
11y
The second ball valves may just need snugged a little ... that usually stops a leak from that location.
The third looks like the joint below the valve is where the leak is/was.
The first may just be the bleeder ... you may be able to snug it as well, but with that corrosion, I'm not sure.
Those valves should have been checked shortly after installation (a few weeks) and then periodically as part of your annual, pre-heating season maintenance.
Investor · New Haven, CT · Member since 2012 · 285 posts · 175 votes
11y
A couple of questions:
When you purge it are you opening up the auto fill manually to allow a full pressure purge? This should force any air through the system.
Are you purging into a bucket and waiting for the air bubbles to stop?
Are you baseboard or radiators?
Also you should definitely have a spirovent installed in any heat system.
Contractor · Rego Park, NY · Member since 2015 · 53 posts · 20 votes
11y
You have an air scoop with an air vent on the boiler which is basically a spirovent, we usually like to install something at the highest point if access allows and if you have a radiator/heater with a fitting that allows easy screw on install. You have an auto fill? What the pressure in the boiler when it cycles and how many stories is the residence?
Philly Burbs, PA · Member since 2015 · 338 posts · 133 votes
11y
Has this always been a problem with this boiler installation, or is this a problem that developed over time?
Do you live close enough to close the feed-water valve and monitor the system to see if it holds pressure?
Is there an unusual amount of condensation on the house windows? I had a boiler leaking between sections one time and it drove me nuts finding the leak. Turns out the water that was leaking was all turning to vapor. Only after I removed the cover from the boiler did I find the leak. It had been leaking so long one of the tie bolts that hold the boiler sections together was rusted through. Damn thing never spilled a drop on the floor.
I had to replace the boiler on that one, but in a way I was relieved. I thought the piping in the slab was leaking. (Levittown house)
Vendor · Norwalk, CT · Member since 2013 · 48 posts · 37 votes
11y
So your air scope is probably not working. It appears it was installed without the 18 inch minimum straight run of piping. The air never really gets a chance to hit the top of the piping in the air scoop. You can change the way it's piped or add in the spirovent should solve your problem.
Investor · Tampa, FL · Member since 2013 · 2k+ posts · 1k+ votes
11y
I agree with @Michael Lovell . The installation wasn't done right. There are other red flags about the competency of the installer. I don't know of any professional that prefers to use compression fittings over sweating the connections together. I would also make sure you have automatic air vents on the runs of the system which look like this:
The old one was leaking so I upgraded it to this:
It automatically bleeds the air out of the system so that you don't have to.
The pump is usually located on the return side, while this can be located on the supply side the diaphragm and expansion tank is also on the supply side not the return.I also don't see the t&p valve but I suspect it is causing the water sitting on the floor, it should be on the water heater side towards the rear of the unit. The main thing I see with this setup is the incoming water never gets bleed until its created a full loop. Look at the manual we will use diagram 9 around here over diagram 10, also might want to make sure right type of tank is installed.