Weil-McLain GV4 Series 2 Boiler Control for Wirsbo Hydronic Floor Heat

Barbarrosa1

Looking for a better way to control a Weil-McLain GV4 Series 2 boiler being used for domestic hot water via a W-M Gold Combo 30 Indirect-fired water heater & supplying hot water for a 3 zone hydronic system. Two zones are Wirsbo in floor tubing heat T86H tstats controlling MVAs on the loops which in turn control 2 circulators through Argo relays. The other zone has some baseboard (upstairs, rarely used) & a "Modine Style" hanging heater in the garage through an Argo relay to control the circulator. The WH 3 way valve is direct wired through the wiring harness on the W-M boiler. The boiler is controlled by a UT 1013-200 control module (just installed to replace the defective 1013-100). Now the boiler is wired so the boiler Grundfos circulator runs constantly & the burner cycles on the water temp limit switch. The temp limit switch has a fixed 30 degree F. differential. Is there a better/more economical way to operate this boiler?

icesailor

Does the internal mixer still work? Or is it stuck in some in between position?

Tim McElwain

That boiler has I believe a system circulator and a bypass circulator. Which one is running constantly?

icesailor

Tim McElwain said:

That boiler has I believe a system circulator and a bypass circulator. Which one is running constantly?

Series 1 & Series 2 came with an internal circulator and no secondary circulator. They both had the thermostat. If you used them as a single zone, you didn't need a second circulator. If you used an indirect or multi zone, you HAD to make the boiler and pump as the primary circuit and do all zones in the secondary circuit. Many installers thought that the second circulator wasn't needed. So they had all kinds of issues. Series 3 and Series 4 had both circulators under the cover and no thermostatic mixer.

The OP has the second circulator but I'll bet it isn't piped like Weil-McLain showed in their I/O manual for a Series 2 Boiler.


http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/discontinued/discontinued-boilers/gv-boiler/gv2manual.pdf

Barbarrosa1

This is the series 2 GV4 with 1 internal circulator plus have the W-M Gold Combo 30 Indirect-fired water heater plumbed in the internal circulator loop. The water heater uses a 3 way valve to either supply boiler water to the heater or bypass the heater. The WH has a wiring harness with plugs that replaces the original boiler plugs on the Gold Control Module so 24V is supplied from the GCM to the WH tstat, the 3 way valve motor & the 3 way valve end switch. Also have 2 radiant floor heat loops, each with circulators & 3 way manual mixing valves. And 1 additional loop with a circulator for the "Modine style" heater in the garage & some baseboard heat upstairs. With the new 1013-200 GCM you have a light that is on whenever the Tstat calls for heat &/or the internal circulator is running. The old 1013-100 GCM did not have that. So I started checking why the Tstat/circ light was always on. No troubleshooting hints for that. Found the wires from the GCM Tstat plug were wire nutted together. Tried operating the boiler from the extra NO connection on the Argo AR821 circulator control for the Wirsbo floor heating loops. Found that caused very short cycling so returned to the temp limit switch control on the boiler (Tstat wires tied together). Per the question about the boiler internal mixing valve operation that may be something that should be checked once the outside temps moderate a little more. Also since the 1013-200 GCM has the contol for a bypass ciculator & a system circulator wonder whether to consider adding the additional pump per the series 4 boiler & doing away with the mixing valve? Comments

icesailor

Fine. is it piped as shown on pages 8, 9, and 10 in the Weil-McLain I/O manual? Most weren't.

Series 2 have the internal mixer that fails and there are no parts available for them. Only a repair and a re-pipe. There are specific I/O instructions for piping that boiler when you do what you want to do. Or are already doing. You asked for information. Its in the manual.

How is it vented? Plexco or Ultravent was supposed to have been replaced because of a recall, only Stainless Steel or other approved venting. PP/Centrotherm would probably qualify.

I don't think that many Series 1 or 2's have thermostatic mixers that still work. Original installers didn't want to be bothered with fixing them. Or the venting. Where I lived and worked, in the 1990's when GV's came out, they sprouted like crabgrass in a lawn. Because they are bomb proof, the bad mixer usually didn't make much difference. The really bad ones, no one bothered to find out why and left them alone. "Rip It Out!!!" When all it needed was a copper cap.

Barbarrosa1

Plastic venting was replaced several years ago on the recall. Now have stainless venting & plastic intake. As far as the piping from the diagrams in my boiler manual & in the Weil-McLain Gold Combo 30 Indirect-fired water heater manual the Plumber/HVAC guy installed as recommended. The installer retired several years ago. Will plan to check the mixer valve when I have a local HVAC firm check the system later this Spring. Plan to install buffered anti-freeze in the system again. Had anti-freeze when installed 22 years ago. Had problems several years ago with air in the Wirsbo in-floor tubing loops & drained a lot of the anti-freeze in the process of bleeding the system. Thanks for your comments.

hot_rod

I thought those early GV had Hoffman brand mixers. Parts are still available for them, it's a B&G Xylem brand.

Sometimes, if you can get the top plug out, they can be cleaned any often they re just stuck from water issues.

It was a nice little boiler in the day, lasted a long time, a pioneer of sorts.

icesailor

hot rod said:

I thought those early GV had Hoffman brand mixers. Parts are still available for them, it's a B&G Xylem brand.

Sometimes, if you can get the top plug out, they can be cleaned any often they re just stuck from water issues.

It was a nice little boiler in the day, lasted a long time, a pioneer of sorts.

What you say, may be true. The story from Weil-Mclain was that the company that made the valve and parts went out of business and no parts were ever available after that. The only resolution that ever came from Weil-McLain was to plug off the by-pass with a copper cap. I have a friend that was really on top of repairing them because he worked for a LP Gas provider. They did installs and installed many GV's. At the time, most all of the Plumbers/Heaters wouldn't do gas piping so the LP gas company did the piping and service. One of the service guys, a friend I nicknamed "Blades" (because he was so sharp) converted many of them. He can tell you anything you want to know about such strange things gas.

Interesting, but at the same time, Weil McLain came out with the WGO, WTGO, SGO oil boilers. They introduced their own burner that they heavily promoted, the QB-150 and QB-300. After selling a whole tribe of package boilers with this QB burner on them, one day, they just stopped selling the burner, No parts, no explanation, no nothing. Almost like a "Non-Disclosure" agreement between two parties in a law suit.

Either way, I don't think I ever saw any one of them connected as Weil-McLain wanted them piped as P/S with a by-pass. The thermostatic valve was supposed to keep the boiler hot. When it didn't work, it killed a lot of boilers. So with the Series 3 and 4 GV's, they put a second 007 in place of the mixer and the boiler pump both under the cover. They still weren't piped correctly.

FWIW.

The secret that no one knows.

Barbarrosa1

Thanks for the info. May try to pull the top plug on the mixer this Spring when I plan to have a local HVAC Co. out to check the boiler over. Might take 2 people to get the plug out after 22 years. Do you know if there is a part number on the valve? Mine has 1" connection to the Grundfos boiler circulation pump, 3/4" connection to the boiler, & a capped 1/2" inlet for a fill line. The fill line & expansion tank/air scoop is plumbed into the boiler return header on my system. P/N according to Weil-McLain in their old manual was 10C541.

icesailor

Barbarrosa1 said:

Thanks for the info. May try to pull the top plug on the mixer this Spring when I plan to have a local HVAC Co. out to check the boiler over. Might take 2 people to get the plug out after 22 years. Do you know if there is a part number on the valve? Mine has 1" connection to the Grundfos boiler circulation pump, 3/4" connection to the boiler, & a capped 1/2" inlet for a fill line. The fill line & expansion tank/air scoop is plumbed into the boiler return header on my system. P/N according to Weil-McLain in their old manual was 10C541.

This is what you are supposed to do. This is the Service Bulletin from Weil-McLain that covers Series 1 and Series 2 boilers. If you are going to do floor heat, with return temperatures below 130 degrees, you MUST repair and replace the boiler piping to match the diagrams shown. They are the same as the original drawings in the I/O manual. It is Service Bulletin SB0401R1.

http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/service-bulletins/SB0401R1.pdf

In the parts list for the Series 1 and Series 2, Items 9 and 10 on page 7 are listed as unavailable.

http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/discontinued/discontinued-boilers/gv-boiler/gv1and2d.pdf

Barbarrosa1

As this boiler has operated for 22 + years as originally plumbed with no major problem other than replacement of the onboard circulation pump, several igniters, vent replacement, & fill valve/expansion tank replacement I see no reason to change out the mixing valve now!

icesailor

You asked about running your GV with low temperature radiant flooring. Weil-McLain says that if you are connecting multiple zones or large zones like radiators where the boiler return water temperatures will be below 130 degrees, that you must pipe Primary/Secondary with a by-pass adjusted so that the return flow stays above 130 degrees as it flows back in to the boiler.

In your OP, you asked for a better way of controlling your system. It wasn't installed properly in the first place. No matter what you do, it should be piped as Primary/Secondary with a Bypass. You can use a Taco "I" Series 4 way mixer and connect the boiler and indirect side to the primary side, and the radiant side to the system side of the 4-way and get boiler protection. That valve would make it Primary/Secondary. You don't even have to add any circulators.

A good way to tell if the internal bypass isn't working properly is if in the right atmospheric conditions occur, and your house is obscured by a fog bank created around the exhaust, and it goes away when the boiler shuts off, the boiler is really condensing.

JUGHNE

I changed our GV, series 2 boiler out for a mod/con boiler for a number of reasons, not necessarily anything to do with any boiler issues. After 15 years the only repairs were the ignition module and the venting recall. It was piped p/s but supplied a variety of loads.
As it was taken out I noticed the exhaust "horn" on the discharge of the boiler where the vent ell connected; the cast iron horn was beginning to erode on the bottom. There is still enough meat there to connect the ell.
Did you look at your CI discharge?

The plug in the top of the mixing valve wasn't too bad to get out as I could lay the unit on its back.

Also the condensate drain hose was 6" short of getting to the PVC floor drain and within 2 years the acidic water washed a groove in the concrete floor. So there was a fair amount of condensing going on.
The boiler is still stored in my basement. Trying to sell it to a guy with an old gravity system.

icesailor

JUGHNE said:

I changed our GV, series 2 boiler out for a mod/con boiler for a number of reasons, not necessarily anything to do with any boiler issues. After 15 years the only repairs were the ignition module and the venting recall. It was piped p/s but supplied a variety of loads.
As it was taken out I noticed the exhaust "horn" on the discharge of the boiler where the vent ell connected; the cast iron horn was beginning to erode on the bottom. There is still enough meat there to connect the ell.
Did you look at your CI discharge?

The plug in the top of the mixing valve wasn't too bad to get out as I could lay the unit on its back.

Also the condensate drain hose was 6" short of getting to the PVC floor drain and within 2 years the acidic water washed a groove in the concrete floor. So there was a fair amount of condensing going on.
The boiler is still stored in my basement. Trying to sell it to a guy with an old gravity system.

Sell it to the guy with the gravity system and have him install a Taco I series 4 way mixer. It will be a wonderful thing. I series valves make gravity systems. ROCK!!!.

It would be interesting to compare your overall cost of operation of your Mod/Con after 15 years to the cost of operation of the GV. Its my understanding that the GV Series 2 boilers had the black painted valve. They came out reasonably easily with a large socket and braced. The Series 1 blue valves are another animal.

Barbarrosa1

When I get a few minutes I will post some pics with the current piping on the boiler. May be a day or two.
Thanks for the info.