Radiant Heat System Controls

[mfg0772]

Hey all - looking for some advice. I have a hydronic baseboard system currently in my house. I've renovated an area and have installed a radiant system in that area. I have a Taco Zone Controller with 4 zones. 3 of the zones are for the baseboard system. The 4th zone valve now controls the radiant zone. I have a Taco 007 circulator on the return side of the boiler. I'm not getting flow through my mixing valve for the radiant system so I need to put another pump after the mixing valve (I think). My question is how to control that pump. I suppose I could use a Taco Zone Switching Relay but that would mean that my thermostat would have to get wired to the relay and the circulator on the boiler would not get activated by the thermostat. I thought that would be a problem but maybe it isn't since I can get free flow through the boiler circulator. I would also have to either remove the zone valve or just manually put it in the open position. If I were to keep the current set up running through the zone controller, is there some other relay that I could get that would be triggered by the zone controller and would switch on the secondary pump?

Thanks for any help. As you can probably tell, I know enough to be dangerous. I can do the work, just want to make sure I am doing it correctly.

 

[fitter30]

Brand , model and size of mixing valve? Take some pics or diagram of its piping? Boiler water temp in and out?

 

[mfg0772]

Taco 5000-3 mixing valve (1"). Attaching a diagram of the setup. Boiler water temp supply is 160*F - 180*F. Assuming return is 140*F (20*F drop from min supply temp).

I noted where I think the new pump needs to go. Zone valves are currently all tied to a Taco ZVC405-5 Valve Control Module (with priority). Zone controller is tied to the aquastat relay via isolated end switch and existing circulator is controlled from the aquastat relay.

 

[fitter30]

Taco 5000-3 mixing valve (1"). Attaching a diagram of the setup. Boiler water temp supply is 160*F - 180*F. Assuming return is 140*F (20*F drop from min supply temp).

I noted where I think the new pump needs to go. Zone valves are currently all tied to a Taco ZVC405-5 Valve Control Module (with priority). Zone controller is tied to the aquastat relay via isolated end switch and existing circulator is controlled from the aquastat relay.

Radiate heat loops size pex and length of loops? Taco 5000 is it 3 series or Hx?

 

[PoorUB]

Taco 5000 is it 3 series or Hx?

What difference does that make? A Taco 5000 regardless of the extra letters in the model is the same valve other than the type of connections, unless I am mistaken.

 

[PoorUB]

Hey all - looking for some advice. I have a hydronic baseboard system currently in my house. I've renovated an area and have installed a radiant system in that area. I have a Taco Zone Controller with 4 zones. 3 of the zones are for the baseboard system. The 4th zone valve now controls the radiant zone. I have a Taco 007 circulator on the return side of the boiler. I'm not getting flow through my mixing valve for the radiant system so I need to put another pump after the mixing valve (I think). My question is how to control that pump. I suppose I could use a Taco Zone Switching Relay but that would mean that my thermostat would have to get wired to the relay and the circulator on the boiler would not get activated by the thermostat. I thought that would be a problem but maybe it isn't since I can get free flow through the boiler circulator. I would also have to either remove the zone valve or just manually put it in the open position. If I were to keep the current set up running through the zone controller, is there some other relay that I could get that would be triggered by the zone controller and would switch on the secondary pump?

Thanks for any help. As you can probably tell, I know enough to be dangerous. I can do the work, just want to make sure I am doing it correctly.

What is running the zone valve to your floor heat? Piggy back a relay to operate the pump from the same control wires.

Make certain you have a high head pump for the floor loops. We usually figured 10 feet of head for a floor and 1 GPM per loop and the pump will be oversized a bit.

 

[mfg0772]

Radiate heat loops size pex and length of loops? Taco 5000 is it 3 series or Hx?

I was mistaken, it must be a 5004. I assume Hx since that is heating only but I compared the spec sheets for all the 5000 series valves and the specs are all the same. Just if it is lead free or not and the connections being the only difference. Right now, I have 2 loops of 1/2" pex that are about 250'. However, longer term, the plan is to add 6 more loops to the same manifold (I have the other ports deadheaded right now).

What difference does that make? A Taco 5000 regardless of the extra letters in the model is the same valve other than the type of connections, unless I am mistaken.

I agree, not sure it matters.

What is running the zone valve to your floor heat? Piggy back a relay to operate the pump from the same control wires.

Make certain you have a high head pump for the floor loops. We usually figured 10 feet of head for a floor and 1 GPM per loop and the pump will be oversized a bit.

Zone valve is tied back to the Taco ZVC405-5 Valve Control Module and a thermostat for that zone. I was figured a little under 10' of head and also assuming 1 GPM so good to get that confirmation. Seems like you might be in agreement with my approach. So my question was coming down to: how do I piggy back a relay?

For the pump, I was going to use another Taco 007 since I have one on hand. Might not be the ideal pump but should handle the head and has plenty of flow.

 

[fitter30]

I was mistaken, it must be a 5004. I assume Hx since that is heating only but I compared the spec sheets for all the 5000 series valves and the specs are all the same. Just if it is lead free or not and the connections being the only difference. Right now, I have 2 loops of 1/2" pex that are about 250'. However, longer term, the plan is to add 6 more loops to the same manifold (I have the other ports deadheaded right now).


I agree, not sure it matters.

Zone valve is tied back to the Taco ZVC405-5 Valve Control Module and a thermostat for that zone. I was figured a little under 10' of head and also assuming 1 GPM so good to get that confirmation. Seems like you might be in agreement with my approach. So my question was coming down to: how do I piggy back a relay?

For the pump, I was going to use another Taco 007 since I have one on hand. Might not be the ideal pump but should handle the head and has plenty of flow.

250 x .03= 7.5 ft. head all 8 circuits would be the same + 3.5 = 12'
Mix valve spec. cold water supply 39-80°. Minimum 27° temp differential
250 x 32 btu's per ft = 8, 000 btu per loop 8 loops 64,000 btu's. = 6.4 gpm
Design on the loops 20° temp drop
007 will work with two zones but not the 8

 

[fitter30]

I was mistaken, it must be a 5004. I assume Hx since that is heating only but I compared the spec sheets for all the 5000 series valves and the specs are all the same. Just if it is lead free or not and the connections being the only difference. Right now, I have 2 loops of 1/2" pex that are about 250'. However, longer term, the plan is to add 6 more loops to the same manifold (I have the other ports deadheaded right now).


I agree, not sure it matters.

Zone valve is tied back to the Taco ZVC405-5 Valve Control Module and a thermostat for that zone. I was figured a little under 10' of head and also assuming 1 GPM so good to get that confirmation. Seems like you might be in agreement with my approach. So my question was coming down to: how do I piggy back a relay?

For the pump, I was going to use another Taco 007 since I have one on hand. Might not be the ideal pump but should handle th

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[PoorUB]

For the pump, I was going to use another Taco 007 since I have one on hand. Might not be the ideal pump but should handle the head and has plenty of flow.

It might, specs show it will do 8 feet of head at 8 GPM.

I guess if you have it, and can not return it, try it, but it is marginal.

 

[Kaizen]

perhaps dumb question but can you isolate that loop and blow air through it to make sure its not plugged? Also did you make sure the mixing valve is not stuck (if it has removable innards)?

 

[TurnipTruck]

Does the zone valve have an end switch that can control the pump? Or if the new pump has a check valve, turn the pump on/off and eliminate the zone valve.

 

[mfg0772]

250 x .03= 7.5 ft. head all 8 circuits would be the same + 3.5 = 12'
Mix valve spec. cold water supply 39-80°. Minimum 27° temp differential
250 x 32 btu's per ft = 8, 000 btu per loop 8 loops 64,000 btu's. = 6.4 gpm
Design on the loops 20° temp drop
007 will work with two zones but not the 8

Thanks for confirming. 8 loops is a bit further down the road and the 007 is free now so no issue switching out to a different pump later when the time comes.

It might, specs show it will do 8 feet of head at 8 GPM.

I guess if you have it, and can not return it, try it, but it is marginal.

Free is free, right? Seems worth it to give it a try now. This is mostly a proof of concept for the wife. Once I get her buy in, then I expect to expand and upsize at that time.

perhaps dumb question but can you isolate that loop and blow air through it to make sure its not plugged? Also did you make sure the mixing valve is not stuck (if it has removable innards)?

I know the loops are not plugged because I was able to purge the air and get water through the drain port on the return manifold. It could be the mixing valve. However, I read that the mixing valve as a minimum required flow of 1 gpm and couple that with the fact that I need flow to feed the cold side and I think it might be stopping the water. I also read somewhere about the hot passing through and coming out the cold side and returning to the boiler. That seems to be happening based on just feeling the temperature of the piping in various locations.

Does the zone valve have an end switch that can control the pump? Or if the new pump has a check valve, turn the pump on/off and eliminate the zone valve.

It is a three wire zone valve. I believe the 3rd wire is for an end switch. I guess that could go back to the zone controller to operate the primary pump as well as to a relay for the secondary pump? The new pump does not have a check valve but I was considering adding one. I noted above that removing the zone valve and or putting it in the manual open position might work.



Appreciate the input so far everyone. Seems like the second pump is needed and my real question comes down to how to I activate both the primary and secondary circulators at the same time as well as the zone valve (although I could remove that). Or maybe the primary circulator doesn't need to be activated. It will likely have other zones calling anyways so it would usually be running but even if it is not, it does not have a check valve in it so water could free flow through it potentially.

 

[PoorUB]

Appreciate the input so far everyone. Seems like the second pump is needed and my real question comes down to how to I activate both the primary and secondary circulators at the same time as well as the zone valve (although I could remove that). Or maybe the primary circulator doesn't need to be activated. It will likely have other zones calling anyways so it would usually be running but even if it is not, it does not have a check valve in it so water could free flow through it potentially.

You will need both pumps running, one pump to satisfy the floor, the other to satisfy the boiler.

With your zone valves, power across terminal 1 & 2 actuate the valve. There is an end switch across terminal 2 & 3 that could be used to run a relay to run your zone pump.