Underfloor heating upgrade help please?

[RidwarePhil]

We currently have a wet underfloor heating system in at extension on our ground floor. The system comprises;

- Grundfoss Alpha 25-60 pump
- 2 port manifold (2 out / 2 back)
- Mixer valve etc

Currently works over another 18msq and is just linked to the existing central heating system so is on at the same tiem as the rads, which is not ideal due to teh lag.

We are starting some internal works and I am keen to instal the underfloor heating into another area 20 msq, and remove 2 radiators.

I have a couple of questions?

- Will my existing Grundfoss pump be ok for the job or will this need upgradng (how can I find out).

- Whats the best way to control the UFH circuit? separate thermostat / controller linked to boiler.

- Can I extend my existing manifold to provide the extra ports or will it be better to by an new one.

Thanks in advance .

Phil

 

[bengasman]

A 25-60 is overkill imho, I reckon it would pull a lot more than what you have.
Due to the extreme lag, ufh should always have separate stat/timer.
Whether you can extend your current manifold will depend on the make; I suppose some can and some can't.

 

[RidwarePhil]

Thanks

I assume then that if the Alpha 25-60 is already installed then it wont do any harm.

Regarding the timer / stat can you point me in the right direction?

At the minute;
- there is no stat in the room,
- there doesn't seem to be any thermocouple / underfloor sensor linked into the system
- the system only comes on when the heating is on

The complete system will be in one large L shaped room. Should I just have one stat switching the whole system on or off

or should I have multiple thermocouples in the floor operating individual valves on the different UFH circuits

How complex would the installation be in either case?

Ta Phil

 

[bengasman]

Just one roomstat in the area with the ufh, no sensors in the floor needed; you care about the temperature in the room, not in the floor.
Any odd roomstat will do, though it is probably easiest to use a wireless model hooked up in a S-plan set up with a separate timer. To get an area warmed up by ufh, you will need to set the timer well in advance, anywhere from 1 to 4 hours for start as well as end. No way to determine how long exactly other than by trial and errror.