Help with central heating project

[nfollows1982]

Hi all,

I've posted a couple of previous questions which have helped me this far but I want to be sure I'm doing a decent job as I'm making the effort so just after a bit more guidance.

I managed to get the central heating drained down using a 3/4" hozelock connector to the bathroom radiator and I'm in the middle of removing and flushing the rads out with a hosepipe.

I've bought multi-directional TRVs and LSV's from Screwfix and I just want to be sure that I can fit the TRV on the return valve? Where the rads are positioned in the rooms, and with position of furniture, they would be more open to the room if they were on the return. Also, horizontal or vertical fitting?

The other thing is I don't have a room stat - do I need one to comply with building regs?

If I don't need to have a room stat would it be good practice to leave one of the rads without a TRV to ensure circulation in case the other TRV's all close when room temp has been reached?

Thanks

 

[D_Hailsham]

1. You must have a room stat to comply with BR.
2. The rad near the stat must not have a TRV.
3. Bi-directional TRVs can go on either flow or return.
4. A horizontal TRV is recommended as the air flow over the TRV is better.

PS Make sure you balance the system.

 

[nfollows1982]

I've currently got a Danfoss 103e5 control unit connected to the boiler which just provides on/off function.

As I would probably go for a wireless thermostat, does the control unit for the thermostat completely replace the Danfoss unit or is it possibly to wire the thermostat into the Danfoss unit?

 

[Agile]

Whilst a stat is required under BR, it is very unwise of anyone who does not have one because, used properly, they can save about 20% on the gas bill!

Tony

 

[nfollows1982]

I've lived with it like that for 7 years since I moved in - no wonder the gas usage is always horrific when the heating is on.

Presumably that's why the boiler seems to be always firing up even when it's on as there is nothing telling it that the rooms have warmed up?

I have read it's 'easy' to fit one into the system, so if someone can confirm that it would be great, along with install instead of/alongside existing timer control.

 

[D_Hailsham]

I've currently got a Danfoss 103e5

That is a single channel timer.

How it the hot water supplied, from a combi boiler or a hot water cylinder?

If a cylinder, is it heated by the boiler or by the electric immersion?

 

[nfollows1982]

The boiler is a Potterton Flamingo RS13:

http://interpart.partsarena.eu/System/DATA/Dx/DS1/installation/2108/I02-2108/I02-2108.htm

That guide is from 1976 so shows how old the boiler may be!

As far as I have always been aware, the hot water is fed from the cylinder which is heated by the immersion heater.

There is a temperature control on the boiler, which it says is something to do with water temperature, but I've never fully understood what that does.

 

[D_Hailsham]

As far as I have always been aware, the hot water is fed from the cylinder which is heated by the immersion heater.

If there are two pipes connected to the cylinder, it will be heated by the immersion heater. If four pipes, it is heated by the boiler.

There is a temperature control on the boiler, which it says is something to do with water temperature, but I've never fully understood what that does.

The control sets the temperature of the water circulating through the radiators.

 

[nfollows1982]

There is a temperature control on the boiler, which it says is something to do with water temperature, but I've never fully understood what that does.

The control sets the temperature of the water circulating through the radiators.

If that's the case, what is the best way to use that?

I assume that if the control is on low, then the radiators will be cooler and therefore take longer to heat up the room and ultimately use more gas?

So if I turned the control up higher, the water temp in the radiator would be higher and therefore the rooms would heat up quicker, using less gas?

 

[D_Hailsham]

Can you confirm that the HW cylinder is definitely heated by the electric immersion and not by the boiler.

Do you have a time control for the boiler? If so, make and model. If it's very old, you should consider changing it to a programmable thermostat.

You are right in thinking that the house will take longer to heat up when the boiler thermostat is turned down, and vice versa. But it does not necessarily mean that you will use more/less gas. Normally the temperature can be set lower in the milder weather as the radiators do not need to give off so much heat.

 

[nfollows1982]

We only get hot water when the immersion has been on, once it's been used up, we have no more hot water until the immersion kicks back on again.

So, I would assume this means the boiler isn't heating the water?

The time control for the boiler is the Danfoss 103e5 that I mentioned earlier in the thread - this just has the digital timer so the boiler can be turned on and off which is programmable for 3 times per day.

 

[D_Hailsham]

We only get hot water when the immersion has been on, once it's been used up, we have no more hot water until the immersion kicks back on again.

So, I would assume this means the boiler isn't heating the water?

It does appear to be correct, but you can confirm this by the number of pipes connected to the cylinder - see my earlier post.

The time control for the boiler is the Danfoss 103e5 that I mentioned earlier in the thread - this just has the digital timer so the boiler can be turned on and off which is programmable for 3 times per day.

Short-term memory!

Provided you are happy with the control the Danfoss supplies, there is no real need to change it. Just install a room thermostat. Wireless is probably the easiest as there is no need to run a cable to the thermostat location.

 

[nfollows1982]

Can confirm it's just the 2 pipes feeding the cylinder.

In terms of the danfoss unit I'm happy with its functions as a timer unit so it is just the thermostat that's required.

What I wasn't sure of is does the thermostat have to be wired into the boiler or can it be wired into the danfoss unit so it just works when the timer is on?

Or can I just remove the danfoss unit and then use the wiring to connect up a new control device for the thermostat?

Thanks

 

[twgas]

I would go for a wireless programmable room stat, the cost is more dependent on make than functionality. The wiring would be, quite possibly, like for like, or at least minimal alteration

 

[D_Hailsham]

What I wasn't sure of is does the thermostat have to be wired into the boiler or can it be wired into the danfoss unit so it just works when the timer is on?

Or can I just remove the danfoss unit and then use the wiring to connect up a new control device for the thermostat?

The thermostat goes in circuit between the danfoss and the boiler. The timer says when the boiler can be on; the thermostat tells the boiler if it needs to be on.

I agree with twgas about a wireless programmable stat.