Honeywell 2 poet zone valve wiring

I’m wanting to wire a Honeywell 2 port zone valve up to a simple on/ off switch using a timer, I.e. live/ neutral and earth.

Which colours will power the motor to open the valve?

I presume it doesn’t need power to close the valve.

Thanks.

You wont frown if you use the brown

to open the valve stu

and the blue

is the neutral

which you need

so its not futile

what are you using the valve for if you are not using the micro-switch wires ?

ianmcd said:

what are you using the valve for if you are not using the micro-switch wires ?

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To zone part of a house.

ianmcd said:

what are you using the valve for if you are not using the micro-switch wires ?

Click to expand...

picasso said:

You wont frown if you use the brown

to open the valve stu

and the blue

is the neutral

which you need

so its not futile

Click to expand...

So brown to live and blue to neutral?!

Wiring to all heating controls should be from one isolation so if not label it so anyone working on it is aware .

your boiler and all controls should be powered by the same fused spur supply

ianmcd said:

your boiler and all controls should be powered by the same fused spur supply

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Why? mine has 10 independent supplies, 9 pairs of AA batteries and one FCU. What is the difference using a TRV with an electronic head, and a motorised valve? Except that the TRV gradually opens and closes and has time clock and thermostat built in and the motorised valve needs external timer and thermostat and is either open or closed and it often has a micro switch built in, they do the same job.

Yes there needs to be some protection so if the supply to a valve fails a pump is not pumping against a closed outlet, and in the main this is done by using a by-pass valve, but most TRV heads state when the battery starts to fail the valve will motor open before displaying fail code. But would not rely on this being the case. I have seen even when the micro switch in the valve is used to power the boiler and pump, where micro switch has stuck, so pump still running.

I would agree where the micro switch in the motorised valve is used, it is good practice to use same circuit (as BS7671 definition) but it is also common for boilers to have internal fuses, so with best will in the world there are multi-circuits in a central heating system. So it seems this is not an electrical requirement, so where is it required? There is a requirement for where possible a single fire fighters switch, but that is not really anything to do with central heating.

I would where possible supply the whole central heating with a single FCU, but today we see items like Nest where you can buy a cradle specially designed so the thermostat is independently supplied from the heat link, yes it is transformed down to 5 volt, but that is from a 230 volt supply. Be it a pair of batteries or a transformer or using the house hold low voltage supply I can find nothing to say a single fuse must be used for all.

ericmark said:

Why? mine has 10 independent supplies, 9 pairs of AA batteries and one FCU. What is the difference using a TRV with an electronic head, and a motorised valve? Except that the TRV gradually opens and closes and has time clock and thermostat built in and the motorised valve needs external timer and thermostat and is either open or closed and it often has a micro switch built in, they do the same job.

Yes there needs to be some protection so if the supply to a valve fails a pump is not pumping against a closed outlet, and in the main this is done by using a by-pass valve, but most TRV heads state when the battery starts to fail the valve will motor open before displaying fail code. But would not rely on this being the case. I have seen even when the micro switch in the valve is used to power the boiler and pump, where micro switch has stuck, so pump still running.

I would agree where the micro switch in the motorised valve is used, it is good practice to use same circuit (as BS7671 definition) but it is also common for boilers to have internal fuses, so with best will in the world there are multi-circuits in a central heating system. So it seems this is not an electrical requirement, so where is it required? There is a requirement for where possible a single fire fighters switch, but that is not really anything to do with central heating.

I would where possible supply the whole central heating with a single FCU, but today we see items like Nest where you can buy a cradle specially designed so the thermostat is independently supplied from the heat link, yes it is transformed down to 5 volt, but that is from a 230 volt supply. Be it a pair of batteries or a transformer or using the house hold low voltage supply I can find nothing to say a single fuse must be used for all.

Click to expand...

well keep Googling

When it comes to wiring, sometimes it's unavoidable to have supplies from more than one electrical supply such as when a 400V system is being switched by 230V controls. So it is allowed when unavoidable, provided notification is present.



When it comes to heating systems there is of course more involved than just wires. Certainly the batteries won't be a problem, but providing more than one 230V supply for the heating system could be. Someone working on the system may turn off the boiler isolator and then get an electric shock via a connected accessory that is powered from elsewhere.

Using a single supply source is good wiring practice, and boiler manufacturers state in their instructions that only one mains supply should be used for the whole heating system. Following the suggestion from @ianmcd...

ianmcd said:

well keep Googling

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...I found the four examples below in a couple of minutes.

Of course using more than one 230V supply would work, and I have seen a couple of DIY / lazy installs, where this has been done, but I have never seen it done by a professional.


Vaillant



Worcester



Glow Worm



Ideal

I have one electric supply to my house, there are some double pole switches, but in the main the the only way to "Isolate" supply is to turn off main incoming isolator, or unplug, the RCBO may have line and neutral to device but it only switches line, and to isolate you need to switch all live wires so has to switch line and neutral. I agree with a TN supply we can get away with only switching line, but must be both with TT supply.

So yes I know the fuse carrier of a FCU is designed to take a lock which will lock off the system, this will make the system mechanically safe, but not electrically safe, so with any system is designed where possible to be made mechanically safe by fitting a single lock.

So if you for example turn off a radiator and remove it to decorate, the valves should not automatically open, to do this the TRV head is removed and replaced with a cap so should the room cool the valve will not auto open, the motorised valve also has a removable head, so like the TRV can be removed to ensure it does not switch on unexpected.

Manufactures of fixed appliances can stipulate extra things, for example a fuse box with xemi-conductor fixes, unlike portable appliances will fixed manufactures can stipulate fuse sizes etc. So @stem is correct to show out dated manufactures requirements. Clearly outdated, as says IEE and has been IET for over 10 years.

I don't have BS7671:2018 I only have the 2008 version, however it seems the must follow manufactures recommendations has now been dropped, likely due to poorly written manufactures instructions, where some daft requirements are stated. The Worcester notice is interesting when it asks for RCD protection with type A RCD. Although I have all RCD protection sure it is type AC not type A. As to getting a RCD FCU type A think that will be hard, most RCBO's seem to be Type B, so with Worcester Bosch it seems one would need a dedicated CU for the RCD to be type A, forget FCU with built in RCD.

So interested how you comply with Type A requirement?

ericmark said:

the motorised valve also has a removable head

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Does It ?????

Not being a plumber I employed a plumber to fit motorised valves in my house, he was not however wiring up the system, so I wired the heads well before he fitted the valves and they sat there acting as relays for 2 months weighting for plumber to do his bit completely disconnected from pipe work.

So looking at heath and safety of the mechanical parts of the system you likely want one isolator for all. But from @stem post the problem is RCD protection Screwfix site lists 16 RCD's all Type AC so not suitable. Look at RCD FCU it does not even say what type other than active or passive. Now the RCBO's (5 pages of them) are all Type B or C which is better than Type A so with a RBCO likely it would comply, but with a RCD or RCD FCU likely it would not.

So needs to have a common isolator for all, the main isolator in the consumer unit will mean that is nearly always complied with, but for it to be situated adjacent to boiler that means in the main you would need a local isolator, I consider an isolator has a means to lock off, where a switch often does not have that option. So a fan isolator would be OK but a 20A light switch would not, the 3A fuse does mean a FCU is required, in a CU the carriers is normally for HRC type aM and gG fuses which one would struggle to find 3A version, and would mean can't use a RCBO, Legrand do a 3A RCBO type B, but the manufactures stipulate fuse. However it also says power switches that's a new term to me, I assume it means MCB, or RCBO but does not say that.

So let him without sin through the first stone, do you really hand on heart follow the manufactures instructions so would you insist on fitting a second consumer unit to house the type A or better RCD before fitting the Worcester Bosch boiler, or would you say a type AC is good enough? And if your happy to not follow that instruction why should you follow any other manufacturers instructions?

ericmark said:

@stem post the problem is RCD protection

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Not quite sure how you came to that conclusion. The references I posted were on the point of connection & isolation, in that the boiler and all of its connected accessories have:

"One common electricity supply"
"Same supply"
"Common isolator"
"Common double pole isolator"

RCD protection is mentioned elsewhere as a separate item.

ericmark said:

So needs to have a common isolator for all, the main isolator in the consumer unit

Click to expand...

You know that's not what is being referred to. Do you really think that when an engineer comes to work on a boiler he will isolate the power to the entire premises at the consumer unit.

@ericmark it's your house you can do what you want, you don't have to try and justify it to anyone else.

@stem in my house the boiler, pump, motorised valve and heat link all supplied from a FCU with 3A fuse which is supplied from a RCBO, and the heat link supplies the thermostat which is battery backed, and all TRV heads have a pair of AA batteries.

You have pointed out however the RBCO should have the not the to show it can work with a DC component. So must be a Type A or better, the normal Type AC is not good enough. Looking at Screwfix can't find a single RCD which is type A they are all type AC, thought the RCBO was type B but then realised this referred to MCB part of unit not RCD part of unit.

I am sure my boiler does not need a type A RCD it is rather old, but I have not considered the boiler requiring a special RCD until you pointed it out with your pictures, as to one FCU for all only the Ideal instructions actually says that, personally electrically I think a socket and plug is better as easy to lock off, however there is a chance some one will unplug the boiler to use some thing else. And the idea of running cables to every radiator just in case in the future some one wants a fan assisted radiator seems daft, the instructions do not say pump, valve, thermostat, or fan, one does say wiring centre but the instructions are so vague as to exactly what the want it would be hard to wire a house to those instructions.

When I go to work the buildings do have more than one supply, so the instructions as to all off same supply does make some sense, however I have never seen a private house with more that one supply, I am sure there are some, but for most homes the instructions must come from same supply can be ignored as they only have one supply.

But the RCD requirement is some thing I had never realised, and I must thank you for pointing it out.