UFH & Radiator on the same zone?

[Bajansam]

Hello all,

 

I have been doing a big house renovation over the past year. Part of that is teaching myself UFH systems. So far i have 5 zones - zones 1-4 are UFH and zone 8 is the radiators upstairs.

 

The problem i have is that zone 3 (the hallway) is not providing enough heat to heat the hallway. The house is an old 1930’s semi with minimal cavity insulation, so it gets cold quickly. 
 

Because of this, i’ve installed a radiator in the hallway and would like to somehow get this running on zone 3. The only way i can think to do that is adding a motorised heating valve to zone 3, however the valve has 5 wires and i cannot figure out how it should be wired.

 

Im using a Heatmiser system with a UH8-RF wiring centre. the motorised valve is a honeywell.

 

Does anyone know how i can wire this, or have any other ideas how i can get that one radiator to activate with zone 3?

Thank you so much for any help, my mind has gone mental trying to figure this out! 

[PeterW]

Is the rad on its own pumped circuit or are you relying on another pump that operates at the same time...? 
 

You can wire two actuators into a zone on the Heatmiser units. Nothing stopping you wiring the zone valve into the Z3 terminals but that will only open the valve. Need a bit more info to drive the rest. 

[Rich123]

Hi , running radiator direct from the underfloor loop would be possible but the output would be very low at the temperatures after the manifold.

There are a number of options , put the radiator prior to the manifold , assuming the primary temperature of the heating is running at 80 c, or using a fan assisted radiator direct off the underfloor circuit .

it could work off its own thermostat to simplify things or a trv.

if you run a radiator at 50 c the output would be reduced to less than half the stated value , there are tables to check this if you go to the stelrad website.

[Bajansam]

45 minutes ago, Rich123 said:

Hi , running radiator direct from the underfloor loop would be possible but the output would be very low at the temperatures after the manifold.

There are a number of options , put the radiator prior to the manifold , assuming the primary temperature of the heating is running at 80 c, or using a fan assisted radiator direct off the underfloor circuit .

it could work off its own thermostat to simplify things or a trv.

if you run a radiator at 50 c the output would be reduced to less than half the stated value , there are tables to check this if you go to the stelrad website.

The radiator currently runs off literally just before the manifold, therefore at 80c. I dont mind running it on its own stat, but would rather have it on the same stat as the UFH in zone 3, if possible? 

[Bajansam]

1 hour ago, PeterW said:

Is the rad on its own pumped circuit or are you relying on another pump that operates at the same time...? 
 

You can wire two actuators into a zone on the Heatmiser units. Nothing stopping you wiring the zone valve into the Z3 terminals but that will only open the valve. Need a bit more info to drive the rest. 

The rad runs off from the 22mm flow and return just before the manifold on its own 15mm circuit, with a motorised valve just after it splits off. The motorised valve is manually set to open, so at the moment it turns on whenever the boiler kicks in for the central heating. That motorised valve i would like to wire into zone 3 as if its like a second actuator, if you see what i mean? 
 

i just cant figure out how to wire the thing because theres 5 wires from the valve...

[Bajansam]

Can i not wire the zone valve in as a second actuator? Or is there an alternative solution

[Nickfromwales]

1 minute ago, Bajansam said:

The rad runs off from the 22mm flow and return just before the manifold on its own 15mm circuit, with a motorised valve just after it splits off. The motorised valve is manually set to open, so at the moment it turns on whenever the boiler kicks in for the central heating. That motorised valve i would like to wire into zone 3 as if its like a second actuator, if you see what i mean? 
 

i just cant figure out how to wire the thing because theres 5 wires from the valve...

OK. 

1. Green / Yellow = Earth
2. Blue = Neutral
3. Brown = Live to motor ( which opens the valve )
4. Orange = Common of call for heat switch
5. Grey = Switched live out of call for heat switch

Connect the blue and G/Y to the same terminals shared by the heating system supply.

Split the 230v feed to actuator / zone 3 output from the Heatmiser and connect that to the brown. That will get the motorised valve to open and close with the actuator. That should be all you need?

[Nickfromwales]

When the Zone valve brown is energised the motor creeps to the open position ( 8-10 seconds will elapse ). When the valve head reaches the 100% open position, it presses against a micro-switch inside the zone valve which is over the orange and grey pair of cables ( 5-wire ) eg to switch on the boiler and pump ONLY when the valve has fully opened. You do not need the switching pair, and you could have just fitted the 3-wire version. Not an issue, but just to help you understand what they do  

[Rich123]

Hi Benjamin , I think that as this is the coldest zone then the use of a zone valve is probably a bit over the top. However you could use a zone valve to the radiator wired in parallel to the underfloor zone . Depending on the existing control system this would need to be either a  similar voltage or you would need a relay to operate the valve. The only other issue is flow through the radiator which should be fine but connecting across the manifold may result in low flow due to the small differential pressure across the manifold.

As this is the hallway then I suspect it is always required to be warm. If the underfloor is configured with the required boiler enable off the controller the heating to a radiator will only operate if the zones are calling for heat and therefore the boiler is firing .

There are of course many solutions , but I would say keep it simple.

[Bajansam]

7 minutes ago, Nickfromwales said:

When the Zone valve brown is energised the motor creeps to the open position ( 8-10 seconds will elapse ). When the valve head reaches the 100% open position, it presses against a micro-switch inside the zone valve which is over the orange and grey pair of cables ( 5-wire ) eg to switch on the boiler and pump ONLY when the valve has fully opened. You do not need the switching pair, and you could have just fitted the 3-wire version. Not an issue, but just to help you understand what they do  

Thank you so much! As soon as i read that it made sense - definitely one of those penny drop moments! 
 

All wired in and working now! Thank you so so much! 
 

 

6 minutes ago, Rich123 said:

Hi Benjamin , I think that as this is the coldest zone then the use of a zone valve is probably a bit over the top. However you could use a zone valve to the radiator wired in parallel to the underfloor zone . Depending on the existing control system this would need to be either a  similar voltage or you would need a relay to operate the valve. The only other issue is flow through the radiator which should be fine but connecting across the manifold may result in low flow due to the small differential pressure across the manifold.

As this is the hallway then I suspect it is always required to be warm. If the underfloor is configured with the required boiler enable off the controller the heating to a radiator will only operate if the zones are calling for heat and therefore the boiler is firing .

There are of course many solutions , but I would say keep it simple.

Totally understand your point. I had already gone OTT with a zone valve! Its all working now so will just leave as is. Thanks anyway!!

[Bajansam]

Amazing how helpful everyone is here! Thank you.