Wireless Programmable stat query??

glowboy77 · 13 Dec 2010

Hi,

I have recently extended off the back of my kitchen, 2 double rads delivering more than enough heat. I have a digi programmable stat in hallway, i set this to comfort of 20degrees and economy of 17.5degrees at minute as have a 3 week old baby so want to keep house pretty constant.

Anyway, when stat in hall says 20degrees i am only getting 18-19degrees in the new extension. I was assuming this is due to the room being much bigger than the hallway?? That said, am i right in thinking that a wireless stat in extension with a receiver in hallway will overcome this.

But when 20degrees in extension, it will be warmer elsewhere in house so will have to turn down trv's etc to balance? Am i thinking along the right lines here? I am after a bit of info before i potentially waste some money on a wireless stat that ain't gonna make a jot of difference.

Thinking of replacing my sunvic tlx digi programmable stat with the same model but wireless (£50), unless any one recommends others.

D_Hailsham · 13 Dec 2010

glowboy77 said:
I have recently extended off the back of my kitchen, 2 double rads delivering more than enough heat.

when stat in hall says 20degrees i am only getting 18-19degrees in the new extension.

Three possible causes:

1. Boiler not large enough for the additional rads;

1. Extension rads not correctly sized for the heat loss;

2. System has not been balanced.

glowboy77 · 13 Dec 2010

Thanks for response,

Boiler has plenty capacity to accept the additional rads, still some 8000 btu left until max preferred output reached. rads get v hot so no issue over flow, i was assuming problem was the temp reaching desired at the hallway stat quicker that in that room as it is a lot smaller?

Ie wouldn't a small room heat up quicker than a larger one?? Developers fault for placing stat in one of smallest areas of house with a rather large double rad not that far from it.

Anyway, would wireless stat in new extension solve my problem? eg get that to temp i want, adjust trv's in other rooms to suit. Also, as its a bigger room with windows and patio doors i would say it is fair to assume it will lose heat quicker than hallway, to that end it can drop a few degrees before hallway stat has dropped the 1 degree to kick boiler in!!

Does that sound about right or am i weeing in the wind again!!

bengasman · 14 Dec 2010

Have a look at faq, there is a section that explains exactly how it stick together.
Roomstat in the hall is a bad idea anyway, and sunvic must be about the worst brand for controllers on the market

pontered · 14 Dec 2010

it could possibly work, sunvic are v.poor go for drayton/acl

but......

you can't just replace a stat with a wireless stat, you need a perminant electric supply to the reciever

D_Hailsham · 14 Dec 2010

glowboy77 said:
Boiler has plenty capacity to accept the additional rads, still some 8000 btu left until max preferred output reached. rads get v hot so no issue over flow, i was assuming problem was the temp reaching desired at the hallway stat quicker that in that room as it is a lot smaller?

If rads are correctly sized for the heat loss in each room, the rooms should heat up at the same rate.

The rads might have a flow through them and get hot, but is it the correct flow rate?

Feel the pipes either side of each rad. There should be a noticeable difference in temperature, which is the same for all rads. If you don't get this, the system needs balancing; see How to balance a CH system

Developers fault for placing stat in one of smallest areas of house with a rather large double rad not that far from it.

You might have answered your own question.

Is the large rad actually in the hall or is it in a room and expected to heat the hall as well?

as its a bigger room with windows and patio doors i would say it is fair to assume it will lose heat quicker than hallway, to that end it can drop a few degrees before hallway stat has dropped the 1 degree to kick boiler in!!

The rads will take care of this if they are correctly sized.

Which make/model stat do you have in the hallway?

Anyway, would wireless stat in new extension solve my problem? eg get that to temp i want, adjust trv's in other rooms to suit.

You could try it, but the stat in the hall would have to go. There shouldn't be any need to adjust the TRVs as they should already be set to the desired room temperature.

glowboy77 · 14 Dec 2010

Thanks for the replies guys, sorry for late response getting back to you, in early and home late.

Sunvic tlx6501 stat in hall, and yes the plan was to change this stat for the receiver and put wireless stat in extension.

Big rad i mention is in hallway, not on same wall but not that far from stat, no TRV on it.

Interesting about sunvic product insight ie they're c**p. Haven't had any prob with them, programmer by boiler sunvic also. However, this winter heating only seems to work at its best ie flow nice n hot when hot water left permanantly on. When HW on program setting ie 2 hrs am and 2 hrs pm, the flow is only warm hence warm rads and house taking longer to heat up??
Could this be a stat/programmer problem?? Should i replace programmer by boiler at same time??

D_Hailsham · 15 Dec 2010

glowboy77 said:
However, this winter heating only seems to work at its best ie flow nice n hot when hot water left permanantly on. When HW on program setting ie 2 hrs am and 2 hrs pm, the flow is only warm hence warm rads and house taking longer to heat up??
Could this be a stat/programmer problem?? Should i replace programmer by boiler at same time??

It's no good changing something in the hope that it will cure the problem; you first have to identify the cause.

Which make and exact model boiler do you have?

glowboy77 · 15 Dec 2010

potterton suprima 50 L

D_Hailsham · 15 Dec 2010

glowboy77 said:
potterton suprima 50 L

Thanks for the info.

How many motorized valves do you have and which type (see pics below)?

View media item 5946 View media item 11762

glowboy77 · 15 Dec 2010

2 of the 2 port type, they simply clip on!

They have range written on them, they're white.

D_Hailsham · 16 Dec 2010

glowboy77 said:
2 of the 2 port type, they simply clip on!

That's put paid to one theory that it could have been a dodgy mid-position valve.

Going back to your observation that: "This winter heating only seems to work at its best ie flow nice n hot when hot water left permanently on. When HW on program setting ie 2 hrs am and 2 hrs pm, the flow is only warm hence warm rads and house taking longer to heat up??"

You seem to be saying the following:

Hot water ON continuously - heating OK as flow is hot
Hot water ON timed - heating poor as flow only warm

What happens when hot water is OFF? Is the boiler continually cycling - running for a few minutes then stopping for a few minutes?

glowboy77 · 16 Dec 2010

When hot water off it behaves as on programmer ie flow only warm, so takes longer to heat up, boiler fires then only stays on for 1min or so max before flashing temp satisfied. When hw just been turned off ch ok, but when water temp in cyl has dropped we have same prob with it.

When hw permanently on boiler fires and stays on for as long as necessary and flow gets v hot before it goes off.

Thermistor has been changed, no difference made.

Wiring problem??? If so, where's it likely to be???

D_Hailsham · 16 Dec 2010

glowboy77 said:
When hot water off it behaves as on programmer ie flow only warm, so takes longer to heat up, boiler fires then only stays on for 1min or so max before flashing temp satisfied. When hw just been turned off ch ok, but when water temp in cyl has dropped we have same prob with it.

When hw permanently on boiler fires and stays on for as long as necessary and flow gets v hot before it goes off.

The boiler is short cycling when only the heating is on. This is because the boiler is producing more heat than the radiators can use. When the HW is on at the same time the excess heat is used up by the HW cylinder.

You say you have a Potterton Suprima 50L boiler, which is a 14.7kW boiler.

I doubt if you know the output of your rads, but you can find the info by using the Stelrad Elite Catalogue (all rads are very similar).

Post the total output of all your rads.

Do you have a bypass valve on your system? It will be on a pipe connecting the flow (immediately after the pump) to the return. If you do, what type of valve is it?

glowboy77 · 16 Dec 2010

ok, i'll do that. Got 16 rads off it, different sizes obviously but i'll work out the output.

One query, if boiler was pumping out too much heat, when only CH on, for rads to use wouldn't the flow pipe immediately from boiler be v hot, mine is only warm?

Only by pass i can see on flow from pump is a sunvic sbv33, red sleeve cap with pressure in bar indicator on it??

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Wireless Programmable stat query??

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