Heating help, radiators and underfloor

young sparky · Sep 21, 2016

Hi fellas,
Usually do alot of industrial work but have taken on a house for a mate, have all the house wired other than the heating, quite new to wiring domestic heating systems and have very little experience to it, I been looking for wiring drawings to make sure I don't leave anything out as the boarders are coming next week but can't seem to find anything online, basically it is a Grant vortex combo boiler outside, with built it frost stat, underfloor heating down stairs with 3 stats controlling it, and radiators upstairs with the one stat controlling it, basically only info I can get out of plumber is that there is 2 motorised valves positioned down stairs (one for underfloor and one for radiators) and one motorised valve upstairs in hot press for the HW, also it's a 3 channel time clock, any wiring diagram would be greatly appreciated as this is first time I have done any wiring of heating and really don't want to miss anything, thanks

telectrix · Sep 21, 2016

a guy on here, leesparkykent, is well versed in heating controls.so are several other members. wait a while till they come on. my knowledge of heating is limited to chucking another log on the fire if it gets cold.

Silly Sausage · Sep 21, 2016

Have you looked at the manual?

http://www.grantuk.com/wp-content/u...rvicing-instructions-DOC89-Rev00-May-2012.pdf

young sparky · Sep 21, 2016

Archy Styrigg said:
Have you looked at the manual?

http://tinyurl.com/zc5to5e

Thanks archy, have came across that but seems to be a bit vague as far as the info goes for the differs valves and the 3 channel time clock and nothing about the underfloor heating, if i could get a bit more detail on it it would be great.
I did find this kind of wiring diagram which makes a lot more sense, https://www.worcester-bosch.co.uk/files/troubleshoot/gas_wiring-guide_smaller_3.pdf but that is for a different type of boiler, also can't find anything on it that has a 3 channel time clock with the underfloor heating

bigspark17 · Sep 21, 2016

Sounds like a simple enough s plan system with 3 motorized valves HW, UFH, up rads, do you know which underfloor system is being used i.e heatmiser...? And check the resource section of the forum theres plenty of info there about s plan systems, rather than you be given the answer it would be better to try and find the answers and do a little diagram of your own and post it up then members could comment on anything you have missed or drawn up incorrectly. This will see you better for future and give you extra confidmce for future installs.

Dan · Sep 21, 2016

Dont know if it'd help but we have a plumbing forum too.

Central Heating Forum - http://www.ukplumbersforums.co.uk/central-heating-forum/

young sparky · Sep 21, 2016

Thanks lads, have found this drawing on a site, basically my question here is the motorised valves and stats for the underfloor heating wired from the underfloor controls, if so then I would need to change this to a 3 channel time clock to be able to control all 3 separately

Leesparkykent · Sep 21, 2016

Are there external pumps for both DHW and CH? Depending on how the systems piped the boiler may require a switched live for both CH and HW. If there are external pumps these will have to be wired back to the boiler as well. If your not sure to cover yourself you will need LNE DHW and CH, LNE for CH pump and LNE for HW pump. so that's 11 cores you may possibly need at the boiler. The UFH manifold is more than likely going to have a pump as well which only needs to come on when UFH is calling for heat.

In your situation I would look at using a heatmiser UH4 wiring centre which everything will be wired back to apart from the DHW and CH pump which will be controlled by the boiler.

young sparky · Sep 21, 2016

Thanks lee, all I was told from the plumber was about the 3 valves that need to be wired and that all is required is a 4 core to the boiler (extra core for the frost stat)

bigspark17 · Sep 21, 2016

Run a twin & earth and a 3core & earth from wiring centre location to boiler posion.

Leesparkykent · Sep 21, 2016

It depends how the boiler is piped. Is it being piped with just a flow and return with no separate DHW feed? I cant understand the logic of buying a combi boiler and using it like a heat only boiler....

bigspark17 · Sep 21, 2016

Are you sure its not a system boiler OP.? Plumber needs to be clearer! Has he 1st fixed all his pipework yet?

young sparky · Sep 21, 2016

Yea it has to be a system boiler as it has a tank in the hot press, my apologies, as he told me this boiler provided instant hot water I had took it for granted it was a combinbut done a little research there and have learnt a little more about combi, regular and system boilers lol

bigspark17 · Sep 21, 2016

That said then, as i said in previous post twin and a 3core wll suffice.!

young sparky · Sep 21, 2016

So is this how you would go about wiring it? If correct the only thing throwing me off is that it needs to be a 3 channel time clock to control DHW, UFH and the CH upstairs

Leesparkykent · Sep 21, 2016

how many ufh zones are there?

young sparky · Sep 21, 2016

3 zones

Leesparkykent · Sep 21, 2016

young sparky said:
3 zones

Heatmiser UH4 is definitely the way to go IMO. No need to use two separate wiring centres then as everything can be wired back to the UH4. Twin and three core and earth to programmer, twin and three core to boiler position, three core and earth to each thermostat position. All the zone valves, UFH pump and cylinder thermostat all connect to UH4.

I would install a rotary isolator next to the outdoor boiler for maintenance purposes.

http://www.theunderfloorheatingcompany.co.uk/wp-content/uploads/2016/04/UH4.pdf

young sparky · Sep 21, 2016

Thanks Lee, much appreciated

young sparky · Sep 29, 2016

Leesparkykent said:
Heatmiser UH4 is definitely the way to go IMO. No need to use two separate wiring centres then as everything can be wired back to the UH4. Twin and three core and earth to programmer, twin and three core to boiler position, three core and earth to each thermostat position. All the zone valves, UFH pump and cylinder thermostat all connect to UH4.

I would install a rotary isolator next to the outdoor boiler for maintenance purposes.

http://www.theunderfloorheatingcompany.co.uk/wp-content/uploads/2016/04/UH4.pdf

Only getting around to this job today, been all over the place as last few days, just wanted to clarify before installing cables, on the drawing for the uh4 it only shows a 3core &dearth going to the timeclock but you have stated you would run a 3 core + 2 core and Earth

young sparky · Sep 29, 2016

Leesparkykent said:
Heatmiser UH4 is definitely the way to go IMO. No need to use two separate wiring centres then as everything can be wired back to the UH4. Twin and three core and earth to programmer, twin and three core to boiler position, three core and earth to each thermostat position. All the zone valves, UFH pump and cylinder thermostat all connect to UH4.

I would install a rotary isolator next to the outdoor boiler for maintenance purposes.

http://www.theunderfloorheatingcompany.co.uk/wp-content/uploads/2016/04/UH4.pdf

Only getting around to this job today, been all over the place as last few days, just wanted to clarify before installing cables, on the drawing for the uh4 it only shows a 3core &dearth going to the timeclock but you have stated you would run a 3 core + 2 core and Earth

Leesparkykent · Sep 29, 2016

yeah because iirc it shows a 3core and earth to a programmable thermostat. if your using a normal thermostat and 3 channel programmer then you need live, neutral, earth, hw on, ch1 on and ch2 on.

rolyberkin · Oct 7, 2016

Got a job similar to this, any recommendations for wireless thermostats, go to to put in two one for a single zone UFH and one for rads? Thanks?

Leesparkykent · Oct 8, 2016

rolyberkin said:
Got a job similar to this, any recommendations for wireless thermostats, go to to put in two one for a single zone UFH and one for rads? Thanks?

Depends on how you intend to set it up..

1: programmable stats for both rads&UFH and a timer for hotwater.

2: Three channel programmer for rads, UFH and hot water with non programmable thermostats.

3 Twin channel programmer for rads and hot water and a programmable stat for UFH.

bigspark17 · Oct 8, 2016

rolyberkin said:
Got a job similar to this, any recommendations for wireless thermostats, go to to put in two one for a single zone UFH and one for rads? Thanks?

Is it a combi or system boiler?

rolyberkin · Oct 8, 2016

Looks like a Heinz 57!

Job is for my nephew who is probably after a bit of a Gucci system and would be quite happy if I specified something which he could control from a smart phone. This is what has just sent me, any suggestions gladly received. I think the boiler may be scond hand and the cvontrols have been thrown in so not a problem if I don't use them.

I have bought a pro-warm underfloor heating water kit, it came with a grundfos Underfloor heating control pack single room thermostatic pump and Heatmiser DS1 thermostat - no wiring centre though. Plumber has fitted a Grundfos UPS2 15-50/60 central Heating pump, a Honeywell V4043H 2 and 3 port motorised valve, Wall Star condensing oil boiler and a 250l direct unvented fabdec pioneer hot water cylinder with an ESI intelligent electronic dual thermostat. I have a RDH10 Siemens digital room thermostat and a Siemens RWB29Si programmer. Would preferably use a programmable wireless room thermostat for the underfloor heating and a wired programmer with a digital wireless thermostat for the central heating.

Leesparkykent · Oct 8, 2016

rolyberkin said:
Looks like a Heinz 57! Job is for my nephew who is probably after a bit of a Gucci system and would be quite happy if I specified something which he could control from a smart phone. This is what has just sent me, any suggestions gladly received. I think the boiler may be scond hand and the cvontrols have been thrown in so not a problem if I don't use them.

I have bought a pro-warm underfloor heating water kit, it came with a grundfos Underfloor heating control pack single room thermostatic pump and Heatmiser DS1 thermostat - no wiring centre though. Plumber has fitted a Grundfos UPS2 15-50/60 central Heating pump, a Honeywell V4043H 2 and 3 port motorised valve, Wall Star condensing oil boiler and a 250l direct unvented fabdec pioneer hot water cylinder with an ESI intelligent electronic dual thermostat. I have a RDH10 Siemens digital room thermostat and a Siemens RWB29Si programmer. Would preferably use a programmable wireless room thermostat for the underfloor heating and a wired programmer with a digital wireless thermostat for the central heating.

If the cylinder is unvented there must be more valves than the two port and three port as the three port would control rads and hot water and the cylinder would require a two port for interlock as a safety feature. TBH its sounds like the plumber isn't that clued up as the simplest way to achieve this would of been 3 x two ports for rads, UFH and hotwater. As it is atm it wont work as the three port will always sit in an open position so if the UFH calls for heat then either the rads or HW will start heating as the three port will always be open in one of the positions.

As for thermostats I would look at Honeywell
Honeywell DT92E Wireless Digital Room Thermostat | Digital Room Thermostats - https://www.plumbnation.co.uk/site/honeywell-dt92e-wireless-digital-room-thermostat/?utm_source=bing&utm_medium=cpc&utm_campaign=Bing%20Shopping%20-%20All%20Products%20-%20No%20Negs&utm_term=1100608002355

Honeywell Y6630D Y6630D1007 Y6630 - http://www.jtmplumbing.co.uk/heating-controls-valves-c436/honeywell-stats-programmable-wireless-c122/honeywell-y6630d-y6630d1007-y6630-pp4052

for programmable thermostats I would look at dryaton mi stats
Drayton MiStat Programmable Thermostat & Receiver MP710R | Wireless Programmable Thermostats - https://www.plumbnation.co.uk/site/drayton-mistat-programmable-thermostat---receiver-mp710r/?utm_source=bing&utm_medium=cpc&utm_campaign=Bing%20Shopping%20-%20All%20Products%20-%20No%20Negs&utm_term=1100608002355

if you want it all to be controlled via an app then heatmiser neo or hive2/hive multizone

Digital Programmable and Room Thermostat Products from Heatmiser - https://www.heatmiser.com/en/

Hive Active Heating™ | Wireless Thermostat & Heating Control - https://www.hivehome.com/products/hive-active-heating

rolyberkin · Oct 8, 2016

Thanks Lee, yes having now genned up on how a three port valve actually works (does help!), I agree he does need three two port valves. The 'plumber' is my brother in law who is a bit rusty so have sent him a mail suggesting he re checks his pipework!

young sparky · Oct 18, 2016

Leesparkykent said:
yeah because iirc it shows a 3core and earth to a programmable thermostat. if your using a normal thermostat and 3 channel programmer then you need live, neutral, earth, hw on, ch1 on and ch2 on.

Hi Lee, sorry to bother you pal but you seem to be the go to man when it comes to heating around here , I'm going back to 2nd fix this tomorrow, the only question was about this extra 2core and earth I was bring to the timeclock, when connecting this at the uh4 does this just connect in with the incoming mains to the UH4, justbwamting to be on the safe side before anything is turned on as it doesn't show this cable on the wiring diagram, thanks

Uheat – Jake · Oct 18, 2016

young sparky said:
Hi Lee, sorry to bother you pal but you seem to be the go to man when it comes to heating around here , I'm going back to 2nd fix this tomorrow, the only question was about this extra 2core and earth I was bring to the timeclock, when connecting this at the uh4 does this just connect in with the incoming mains to the UH4, justbwamting to be on the safe side before anything is turned on as it doesn't show this cable on the wiring diagram, thanks

From my experience with the UH4 there isn't a facility to use a Time Clock for the UFH with a UH4, the UH8s are the only ones which offer this feature and that's when using manual thermostats.

If you're using a standard Thermostat for the HW control then it's always been advised that a Three Core and Earth is used as per wiring diagram.

Correct me if I'm wrong?

Leesparkykent · Oct 18, 2016

young sparky said:
Hi Lee, sorry to bother you pal but you seem to be the go to man when it comes to heating around here , I'm going back to 2nd fix this tomorrow, the only question was about this extra 2core and earth I was bring to the timeclock, when connecting this at the uh4 does this just connect in with the incoming mains to the UH4, justbwamting to be on the safe side before anything is turned on as it doesn't show this cable on the wiring diagram, thanks

Hi mate, what controls are you using? Do you have a 3 channel programmer which 1 channel is for the UFH, 1 channel for the rads and the other for hot water? you aren't using programmable thermostats just non programmable ones? To pick up a permanent feed for the programmer it would be best to take it from L E N from one of the zones this way it protected by the wiring centres internal fuse.

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Silly Sausage

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