WeilMclain GV4 Series3 88000 BTU out, NG boiler

Docfletcher

19/20psi at 80F and 20/21psi at 180F



This is a 20 year old system. 7 zones, but only 4 currently in use. Also a Bock indirect, also 20years old.



Serviced expansion tank after PRV started dripping. Then cold fill to 14psi and left it cold for 8/10 hrs and the psi was still 14psi. Used test gauge to verify it.

Powered boiler up and as the water got hot pressure increased to 20/21psi at 180F. When the boiler went cold overnight the pressure did not decrease to the expected 14/15psi. System has been running like that for several days now with no change except no more PRV dripping.



I repeated the above 2 times and the same symptoms repeat. I could use advice please. Thanks.

Tim McElwain

Are you getting any flash codes on

boiler control?



It sounds like you expansion tank may need some attention from a professional. An increase in pressure with the boiler running is an indication that the diaphragm tank is not allowing for expansion and may need replaced.



Do you have two circulators inside the boiler, one a system circulator the other is a bypass. Sometimes if the bypass is not functioning the same problem can arise. That is why I ask about the flash code.

Docfletcher

Expansion Tank

Was replaced last fall. I just took it off it's mount and serviced it . Set it to 14psi, same as fill psi. No water when air released.from tank.



No codes. Boiler is defying the laws of physics.



One circulator inside boiler.



http://screencast.com/t/hFIcGrrLEN



http://screencast.com/t/hYoWqa94I



http://screencast.com/t/DGKAWDxB7Zex



http://screencast.com/t/gEEALMsE

icesailor

Zone Valves:

Is there a flow control/flow check on the system?

Those are new circulators. Are there IFC (Internal Flow Checks) inside? If so, take them out. The zone valves are motorized flow control valves. If there is a flow control on the second zone and it has zone valves. open it. You can isolate the system from the pressure/Extrol. tank from the system when the zone valves are closed and a flow check valves are closed.

I'm only going by what I can see in the photos.

Docfletcher

Sorry, It's Series 2 not Series 3

I'm really sorry about my screw up. It has the mixing valve instead of the return circulater.

Tim McElwain

You could have check valves in the

piping system, or you have a valve shut of somewhere restricting flow.

icesailor

Series 2 GV4's.

If it is a Series 2 with the thermostat, many strange things happen to that boiler when the internal valve fails.

A year or so ago, there was a big discussion woth someone that had one with the broken thermostat.

Seriously though. If you have IFC's in the circulators with those Taco 572 zone valves, you don't need IFC's or ANY flow checks. The zone valves are the flow checks.

You really need some piping weenie to look at it. Its not simple, but it really is.

Tim McElwain

You need to get

a professional involved as the mixing valves on Series 1 and 2 were a problem. Have your professional go to Weil McLain website and look up Technical Service Bulletin SB0401R1, Feb 25, 2004. That explains the problem with the mixing valves.

Docfletcher

Circulator Etc

Circulators in the photo are 20 year old Taco 007F's . There are no check valves anywhere in the system except over the UP Grundfos 15-42fr on the Bock indirect water heater.This problem occurs while the boiler is working to service the Bock. The only time I used the heating zone valves this year was to ensure no air in system,



This boiler has been acting strange since last October, though not with this current problem. Was leaking pressure release.



Last November I replaced pressure release valve, the BFP, pressure reducing valve, tank, and the temp limit assembly including the well. I replaced all the zone valves and provided ball valves with unions for easier servicing. The Sparco's that were there were shot. System and boiler ran fine till about Aug 1 of this year when the pressure release stated leaking again.



IA friend and I installed this system as a conversion from hot air to hot water baseboard.

Looks like we screwed up as both the Bock circulator and the tank are on the return side. Oh yeah, but it worked fine for 20 years

Docfletcher

Ice Sailor... Elaborate Please

What do you mean by "With The thermostat" ? It has the limit assembly that insets into well. Which by the way was new last fall. I am having a issue with it because I can't set it to 180F as it will not flame off there. In order to get the boiler to flame off at 180F I have to set it at 165F. After it turns off heat soak takes it to 190F.



Tim thanks for sharing the TSB on the mixing valve. It looks like the fix (IF Bad) is to plug the hole and simply re-pipe the rest with iron or copper. Effectively doing away with the mixing valve.

icesailor

Plugging Holes:

Usually, you just need to plug the hole. Re-piping is an option. Like Tim said, get the Tech Bulletin. There was a long and comprehensive discussion on this issue last year.

It sounds like you might have a leak in the High Side of the indirect, leaking back into the low side boiler pressure. That temperature and thermal lag can be due to a bad thermostat. If you find the discussion, there is a guy I know who posted here. There is a difference in the colors of the thermostat valve. You need to find out. One is not so hard to get out, the other is extremely difficult to get out. That person chose to replace and re-pipe the whole boiler because they couldn't get the plug off. He had the wrong color.



Maybe someone can lead you to the discussion.



Good luck.

Docfletcher

Dink'ed Around With It A Bit!

I bought the new superstor indirect due to the Bock's age and i suspected a leak into the coil from the high side. However, time and time again that has proven to not be the case. Cold filling the boiler using the the pressure reducing valve and letting the boiler sit for 12/14 hrs shows no increase in psi. I ran this test again overnight using a brand new test gauge.



I think the calibration is off a little on the high limit side of the thermostat since 165F seems to equal 180F. I can live with that as the low limit is right on the money at the factory set of 140F.



I replace the limit assembly last year. I did not use any thermal conductive paste. I might try some to see if it improves accuracy.





Last night I reduced the PSI in the expansion tank to what I believe is 12psi from 14 psi. I'm not 100% sure because the the air gauge I used crapped out at the last moment. Such irony should not befall one as anal attentive as I. Anyway, now shes running at a steady range 14/15psi. 17/18psi. That's best as I can actually tell because the test gauge is mounted a little over 2 ft higher than the boiler gauge. So at least now I have a range of pressure.