Weil McClain Boiler Question


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Old 02-18-14, 08:35 AM
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Weil McClain Boiler Question

I have a GV-5 series 1 WM Gold boiler that is connected to a WM Combo 30 hot water holding tank. I raised the temp. setting higher on the Combo 30 stat but now see the water stops circulating to my baseboards when the boiler is supplying hot water to the combo 30 . There is a diverter valve piped into the boiler supply line that opens for the combo 30 but shuts off flow to the base boards . I have 4 zones and during the past few weeks could not figure out why the baseboards are cold even though the room stats are calling for heat. I have 4 Taco circulating pumps and 4 Honeywell zone valves. Is the set up common for the Weil McClain?
Thanks
 
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Old 02-18-14, 08:43 AM
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Hello...

Most likely whatever control you have is set for priority of the indirect...

The heat will hold off for sometime while the water heater recovers... Usually its temperary and time based at 20 minutes or so.. After that time the heat loops should start functioning again...

If you do not like that feature you can turn it off...
 
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Old 02-18-14, 09:58 AM
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Weil McClain with Combo 30

It's factory wired to divert the valve open to the Combo 30 when the stat on the water heater tank is calling and close that loop and open the baseboard loop when water temp. is satisfied. I can see the lever open and close on the valve by adjusting the hot water tank aquastat. I raised the temp to a higher limit over the winter, but by doing so caused flow to the baseboards to be shortened.
 
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Old 02-18-14, 10:10 AM
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What control powers the indirect zone?

Is there a taco control panel?

Can you take pics of the system and controls?
 

Last edited by lawrosa; 02-18-14 at 11:36 AM.
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Old 02-18-14, 10:29 AM
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Weil Mclain Combo 30

I can see a Taco circulator mounted on top of the boiler which comes on and pumps boiler water to the Combo when the Combo water temp. stat calls for heat. In addition the Combo tank water stat opens the two way valve port to the Combo 30 tank and closes the port to the baseboard supply line. This valve is plumbed on a 1" line right out of the boiler. I don't think there is a malfunction, only am now aware of what having hotter domestic water has on the baseboard getting hot water from the boiler.
 
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Old 02-18-14, 10:59 AM
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Just to clarify a bit for Mike because it doesn't sound as if he's familiar with this exact boiler... the GV series of boilers have a 3-way diverter valve as part of the boiler. It is controlled by the boiler controls. When the DHW calls, the boiler flow is diverted to the DHW tank, and when the heat calls, the valve goes the 'other' way, to the central heating system.

It's been a while since I looked at this boiler myself, and I don't remember if there is a priority 'time out' or not... there may be a setting for that but I think not... as I recall...

DV, what you are describing is basically normal operation, the nature of the beast.
 
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Old 02-18-14, 11:08 AM
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Zoca,
I edited my thoughts because trooper posted at the same.
 
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Old 02-18-14, 11:44 AM
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Just to clarify a bit for Mike because it doesn't sound as if he's familiar with this exact boiler... the GV series of boilers have a 3-way diverter valve as part of the boiler. It is controlled by the boiler controls. When the DHW calls, the boiler flow is diverted to the DHW tank, and when the heat calls, the valve goes the 'other' way, to the central heating system.
Im very familiar with the GV...Its a 1990's era boiler.

This was a kind of a first attempt at onboard P/S circ to control temps...

From what I know it does not divert to an indirect...????






But to the OP... Is this your boiler?

http://www.weil-mclain.com/en/multim.../gv3manual.pdf
 
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Old 02-18-14, 12:09 PM
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WM Boiler

Your right on NJ Trooper,
I didn't realize that the DHW has priority on the 3 way valve, and spent days trying to figure out why the baseboard in my rancher which comprises of 3 zones would not get hot. The Taco pumps would constantly run through the thermostats demand but there was no hot water flow going through them. Really had me thinking problem was an air bound system which led me to bleed the zones. End result was no change in hot water reaching the zones. Since I lowered the DHW stat I'm getting flow and room stats getting satisfied.
I need to figure out a way to get hot water quicker to the bathrooms which are at the other end of the house from the boiler and DHW. Is heat tape an option on the hot water lines feeding the bathrooms?

lawrosa,
The attachment is a series 3 boiler, mine is the series 1. The most obvious difference is the system circulator pump #6 which mine doesn't have. Series 1 has the #7 bypass circulator pump which is what supplies hot water to the DHW tank coil. That pump works in conjunction with the 3 way valve.

Thanks Guys
 
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Old 02-18-14, 12:26 PM
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The Taco pumps would constantly run through the thermostats demand but there was no hot water flow going through them
That's not really a 'good thing'... controls should have been set up such that the pumps for the central heating don't run when the boiler is serving the DHW.

Is heat tape an option on the hot water lines feeding the bathrooms?
No, I don't think you will have any joy with that. Heat tape doesn't really provide much heat and certainly nothing that will provide any USEFUL heat to the bathroom.

With some repiping you could do a 'home run' back to the boiler. This would get hotter water, faster, to the bathrooms. You're talking about HEATING water and not DOMESTIC hot to the taps, correct?
 
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Old 02-18-14, 12:42 PM
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Well here is the series 1...

I must be missing something then in regards to a combi valve...


http://www.weil-mclain.com/en/multim.../gv1manual.pdf
 
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Old 02-18-14, 12:43 PM
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Troop might know something I dont since he has been around since the horse and buggy...
 
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Old 02-18-14, 01:11 PM
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Troop might know something I dont since he has been around since the horse and buggy...
And the old gray stallion ain't what he used to be! at least his memory ain't!

My apologies, but the GV is not the boiler I'm thinking of. That 3 way diverter valve was added by the installer.

W-M DOES in fact have a model that includes the 3 way diverter as part of the boiler trim. But it's not the GV...

So, what I'm thinking is that an installer that was familiar with that other model (which I can't remember the name of) thought it would be a good idea to duplicate the setup on this system...

OK, it's the CGt that has the 3-way, not the GV, my bad... sorry!
 
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Old 02-18-14, 03:33 PM
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OK, it's the CGt that has the 3-way, not the GV, my bad... sorry!
Not to stray but I would like to see the documentation on that.... Ill look around but I never saw one...
 
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Old 02-18-14, 03:49 PM
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I would like to see the documentation on that
I don't think they've sold many of these... all I could find is the part list... item 10, page 4

http://www.weil-mclain.com/en/multim...parts_list.pdf

Found manual:

http://www.weil-mclain.com/assets/pd...0-290_0212.pdf
 
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Old 02-18-14, 10:48 PM
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Is this what you're looking for:
Well McLain GV Series 1 [PDF]
 
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Old 02-19-14, 04:59 AM
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Your right on NJ Trooper,
I didn't realize that the DHW has priority on the 3 way valve, and spent days trying to figure out why the baseboard in my rancher which comprises of 3 zones would not get hot.
I remember them yes, but the indirect is not to be piped from that 3 way...

There is a diverter valve piped into the boiler supply line that opens for the combo 30 but shuts off flow to the base boards
.

No way IMO....... Something is piped wrong.... That is just a boiler bypass...

Either that or I got into troops dental medication..
 
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Old 02-19-14, 05:04 AM
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Weil McClain GV-5

Guys, I have two issues; 1, The Taco circulating pumps through thermostat demand in 3 zones run when there is no flow coming from the boiler because the flow is being diverted to the DHW unit. How can this be controlled to switch off the pumps and zone valves until the DHW is satisfied?

2, How to get domestic hot water from the DHW unit to the bathrooms quicker as the distance is about 80 ft. Do I need flow valves and a circulating pump?
 
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Old 02-19-14, 06:09 AM
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1, The Taco circulating pumps through thermostat demand in 3 zones run when there is no flow coming from the boiler because the flow is being diverted to the DHW unit. How can this be controlled to switch off the pumps and zone valves until the DHW is satisfied?
Take pictures of your system please.... We would like to see all piping...


2, How to get domestic hot water from the DHW unit to the bathrooms quicker as the distance is about 80 ft. Do I need flow valves and a circulating pump?
Add an aftermarket recirc pump... For retrofit applications...

Instant Hot Water Recirculating System - What's New - Watts
 
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Old 02-19-14, 08:03 AM
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Weil McClain GV-5

OK, I'll take some photos when I get home. Regarding the Watts recirculating system, is the pump pressure greater than then the cold water street supply pressure thus allowing the hot water to force the cold water back through the lines to the DWT?
 
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Old 02-19-14, 08:15 AM
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, is the pump pressure greater than then the cold water street supply pressure thus allowing the hot water to force the cold water back through the lines to the DWT?
It is thermostaticly controlled with the undersink check valve...

It pushes the cold water out of the hot line and into the cold line. Once the hot line reaches 98F the check valve closes. This way there is always 100f water or so in the hot line. But it does not stay open long enough for the cold line to have hot water in it..

Otherwise you would be running the cold water and it would come out hot...

Hope this makes sense...
 
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Old 02-19-14, 08:28 AM
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Weil McClain GV-5

The downside I see is the DHW will try to maintain temp setting which will increase due to demand from cold water flowing back to the tank. This situation will cause baseboard zones to not be supplied as the boiler tries to satisfy the DHW tank demand. Catch 22?
 
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Old 02-19-14, 09:11 AM
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The downside I see is the DHW will try to maintain temp setting which will increase due to demand from cold water flowing back to the tank. This situation will cause baseboard zones to not be supplied as the boiler tries to satisfy the DHW tank demand. Catch 22?
I dont think that will be an issue at all...

After we see some pics of your system and controls with can make a better judgement call.. Espeacially how the indirect is actually ties into the boiler...
 
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Old 02-19-14, 01:59 PM
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Weil McClain

Here are some photos of the DHW unit piped to the boiler. The 3 way is controled by the stat located on the back of the DHW unit. There is a circulating pump mounted on top of the boiler that circulates the water through the DHW tank to raise the water temp. The baseboard supply is coming from the top of the 3 way valve.
The baseboard return and DHW return are T'd back to the boiler.
 
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Old 02-19-14, 04:56 PM
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This is your actual manual and that 3 way zone valve does not belong there...

http://www.weil-mclain.com/en/multim.../gv1manual.pdf

They are using the onboard circ as the main circ it looks line...

But..

I have 4 Taco circulating pumps and 4 Honeywell zone valves.
Can you show these circs and zone valves and the controls for them?

Looks like that is a 3 way zone valve used for the indirect and your best off removing that 3 way and installing a circ and flow control...

To make sure is that Indirect a weil McClain? I would like to find the documentation on that...
 
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Old 02-19-14, 05:08 PM
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The units that came with the 3 way valves as troop pointed out, had onboard tankless coils on them. When the tankless coil could not keep up the valve would just loop the water around the boiler to gain maximum temp.

What you have there is wrong and am not sure why anyone would do that...
 
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Old 02-19-14, 05:20 PM
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Weil McClain

How do you suggest the DHW tank should be piped from the boiler?
 
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Old 02-19-14, 05:33 PM
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Well I understand they made these 3 way valves...

http://www.weil-mclain.com/en/multim..._gold_plus.pdf

IMO it was a bad design. Let me research more..

I would make the indirect its own zone if I were to repipe it.. Integrate it with your other zones...

If we can see what you have...

But! Is it working for you? How long will the indirect actually call for heat and stop the heat to the home?

Im trying to find out if its time based or not...
 
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Old 02-20-14, 05:21 AM
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Weil McClain GV-5

This is the first year it's become an issue. We bought the house in 05 and have not been concerned about the baseboard not warming up enough to satisfy the room stats. This year the 0 and single digit temps in addition to me raising the DWH temp caused the system to starve the baseboard for hot water. I lowered the DWH stat and with the outdoor temps getting milder the issue is less problematic.
 
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Old 02-20-14, 05:24 AM
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More pics please...

I can post a diagram later of the prefeered piping scheme..

Still like to see the controls and zones..

How many t stats in the home?

You say 4 circs and 4 zone valves?
 
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Old 02-20-14, 06:48 AM
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Weil McClain GV-5

I'll shoot some photos tonight when I get home. There are in fact 4 thermostat controlled zones although the zone for the unfinished basement and the length of the entire house is never turned on. The three upstair zones are 1) the kitchen -living -dining area. 2) the 3 bedrooms. 3) the 2 main bathrooms. The 4 Taco 07 pumps located in the central part of the basement ceiling supply the zones baseboard with the 4 Honeywell zone valves on the end of the runs near the pumps.
 
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Old 02-20-14, 08:06 AM
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The 4 Taco 07 pumps located in the central part of the basement ceiling supply the zones baseboard with the 4 Honeywell zone valves on the end of the runs near the pumps.
This is bizarre... there is absolutely no reason to have BOTH pumps AND zone valves.

Either NO zone valves and a pump for each zone,

Or ONE pump and a zone valve for each zone.

Not both...
 
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Old 02-20-14, 08:23 AM
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Weil McClain GV-5

That's bizarre that Weil McClain shows on their GV Series 1 Manual how my system is piped on Multiple Zones with Circulators, figure 8, Page 9.

http://www.weil-mclain.com/en/multim.../gv1manual.pdf
 
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Old 02-20-14, 08:44 AM
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I don't see anything bizarre about that at all.

Don't confuse a 'flow control valve' with an 'electric zone valve', they are not the same thing.

A 'flow control valve' is basically a 'check valve' that only allows flow in one direction, they are NON-electric and the purpose of them in that diagram is to prevent flow in one zone from creating flow in another zone.
 
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Old 02-21-14, 07:01 AM
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Weil McClain GV-5

I see what your saying. But I still don't understand how the DHW tank should have been piped to prevent the circulating pumps from not receiving boiler water when the domestic water is calling closing off the 3 way feed.
 
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Old 02-21-14, 07:10 AM
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The three way valve should not have been used at all.

The indirect tank should have been piped as if it were simply another zone, which for all intents, it is.

If the indirect tank requires 'priority' in order to heat the water, it should have been done with proper controls rather than a diverter valve.
 
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Old 02-21-14, 12:04 PM
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Weil McClain GV-5

If I were to replace the 3 way valve with a zone valve similar to my other zones and tie in the existing control from the DWH, wouldn't that work even though there would be no priority?
 
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Old 02-21-14, 12:09 PM
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Yes, it would work fine, and if you used a Taco zone panel, you can still have the priority.

If you are doing any repiping at all, my advice would be to get rid of the electric zone valves at the same time... you don't need them... but:

If your pumps do NOT have internal flow check valves, you would have to replace the zone valves with flow check valves.
 
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Old 02-21-14, 12:21 PM
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Weil McClain GV-5

Cutting out the zone valves would entail a lot of plumbing and bleeding the system. Would the system be more efficient, what is the down side of as is? I do know of one benefit with eliminating the zone valves, and that would be eliminating the water hammer I'm getting from the some valves closing and some pumps still running.
How would the Taco priority control panel work in conjunction with my other 4 zones?
Thanks
 
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Old 02-21-14, 12:56 PM
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How would the Taco priority control panel work in conjunction with my other 4 zones?
The Taco panel would control all of the pumps.

See:

SR506-EXP-4 - Taco SR506-EXP-4 - 6 Zone Switching Relay w/ Priority

You can download the manual and see how it's wired. Basically, all the thermostats including the one on the indirect wire to this panel, along with all the pumps. 120VAC power goes to it, then a single pair of wires goes to the boiler to fire it.

Yes, close a zone valve on a running pump and they can hammer... but usually only if they are installed backward.
 
 

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