Well McClain GV90+4 Takes To Long To Heat Up Rooms

mpinto23 · January 18

Hello all,

I have a well mcclain gv90+ 4 zone boiler that used to work perfectly until last year. It takes over 2 hours to heat up each zone by 1 degree I normally have it at 70 and takes about 2 plus hours to keep it at that temperature. My house is 3,300 square feet. I had plumbers come and take a look and couldn't find anything wrong. I do see that it keeps cycling on and off. i had never had any problems with prior and it used to heat up the zones within 15 to 30 minutes. Any help would be appreciated.

Ironman · January 18

Too little info.

Using setback is generally not recommended for a high efficiency hydronic system.

How much are you setting the temperature back?
Is the boiler operating on outdoor reset?

Are you located where most of us are expecting one of the deepest cold snaps in many years?

What’s the high limit water temperature setting on the boiler?

What type of radiation do you have?

neilc · January 18

boiler cycling on and off on temperature, or are you seeing error codes?

if boiler is making heat, and it's not getting to the house, circulator, or valves, can you post pictures showing what you have,

EdTheHeaterMan · January 18

Too many reasons for your problem, more info needed

GV90+ can have poor performance for several reasons

High limit is set to low and the boiler is not getting hot enough to heat the rooms
Air in the radiators or baseboards. if there is air in the system then the heat transfer medium (Water) can not move as much heat.
Sludge or other debris is blocking the water flow in the pipes. Slow moving water can only transfer heat from the boiler to the radiators slowly.
Valve partially closed restricting water flow. Slow moving water can only transfer heat from the boiler to the radiators slowly.

Look on page 79 and 80 of the I/O Manual for more Troubleshooting. GV 90+ Manual.

What kind of zones do you have? In Floor radiant? Cast iron Radiators? Baseboard Hot Water. Is there any PEX tubing used in your system? Does the system leak water regularly All these factors can be a cause for concern.

hot_rod · January 19

systems that degrade slowly over time like that may have filters or y strainers that need service.

If it worked fine for?? many years?

mpinto23 · January 19

I have 4 zones two on the first floor and two on the second floor. Boiler is located inside the garage where it's warm as well. I have baseboard through out the house. 3 of 4 zone valves have been replaced last year. Limit is at 180 degrees. I have a hvac company come ever year to maintain and flush the boiler. I leave in NJ I know it's been colder than last year but it doesn't really matter if it's 45 degrees or 10 degrees the result is the same on heating stays on for about 18 hours straight. But if it's lowered from 70 to 63 works fine. Last but not least no error codes. Boiler is about 13 years old now.

hot_rod · January 19

if it once worked fine, kept up on the coldest days, then something has changed that should be fixable

You need a knowledgable hydronic troubleshooter willing to check all the variables. Unless that is you?

Flushing every year should not be needed. That just adds more scaling minerals to the system.

Tom_133 · January 19

My best guess with the little info is one of the internal pumps have failed. Or the return sensor is giving it bad numbers and the internal pump that feeds the supply isn't ramping up enough. Any lights on in the boiler? Can you show us how its piped?

Ironman · January 19

” I have a hvac company come ever year to maintain and flush the boiler.”

A hot water hydronic system or boiler should not be flushed unless an issue is present that would dictate the procedure or the boiler is being replaced - particularly when you have copper baseboards. Doing so is actually harmful to the system because it introduces fresh oxygen and minerals into what is a closed system. Any contractor that would do this is actually harming your system.

Water heaters should be flushed regularly because they are on an open loop where minerals can build up, but not boilers.

AJCimino · January 19

gv-series-1-and-2-users-manual_1.pdf

on GV boilers, there is a thermostatic mixing valve that can fail. When this happens it doesn't open to allow heated water into the supply. It is a means of protecting the boiler from thermal shock. Its located under the jacket. The fix is to open the top and remove the element. Weil-Mclain had a bulletin about this instructing the repairer to use a 1/2" copper cap to seal the bottom opening of the mixing valve. I never found this to be a good method. Leaving the thermostatic element out never (in my experience) caused any problems. Also, I don't believe the part is still available. On the attached parts list the mixing valve is shown on top of the block. Now, it is not an easy task to remove the plug. In the past. I've used large pipe wrenches with cheater pipes; usually a two man operation. The short cycling on and off is your strongest hint. The other possibility, as was mentioned, is your internal circulator has failed. That is an easier fix. This also occurs on some Burnham and Peerless boilers.

mpinto23 · January 19

Thank you all. I think I'm just going to replace the unit with a combi boiler. Any recommendations on which is the best any help would be helpful.

AJCimino · January 19

Review attached file, which I believe addresses your problem.

Weil-Mclain Service bulletin.pdf

Jamie Hall · January 19

https://forum.heatinghelp.com/discussion/comment/1836197#Comment_1836197

Sometimes a combi is the best option. But… remarkably rarely. Do your homework on sizing very very carefully.

Ironman · January 19

A combi is a bad choice in most instances.

A heating boiler + an indirect tank will be a much better choice.

Tom_133 · January 20

https://forum.heatinghelp.com/discussion/comment/1836197#Comment_1836197

Where are you located? If you are close enough to me, can I have your old boiler?

mpinto23 · January 20

I'm located in toms river silver bay area. Thank you for your suggestion on the separate units. Which brand would guys recommend for both heating and indirect water.

hot_rod · January 20

A combi can be an excellent option, if your DHW requirements fall within their capability. I've owned and lived with a number of brands and capacities without a single issue.

In some cases a single boiler with a HPWH makes sense also. Two separate systems. Two different fuel sources.

Some of the GV had a mixing valve, some used a mixing pump, later on. Either is repairable, depending on the age and condition of the boiler itself?

Well McClain GV90+4 Takes To Long To Heat Up Rooms

Comments

Categories