ASHP: lagging pipes in loft

gterr

Update:

Compressor, fan, HW heating and aux electric heater remained on until 9.43am. Now all are off. I don't know what time they came on this morning - before 8.30am anyway.
HW temp currently 59, flow temp 44, outside temp 3.
Cold overnight last night: probably min temp about -3 C. Thick frost and some icy roads today.

U/F zones failed to reach their target temps this morning before they were backed-off by the timer/stat to their daytime targets at 9.30am. (This is typical). Dining room coil still open since this room cannot even achieve its daytime target of 18.5 C. (This is also typical: coil may well stay open all day).

Cheers.

lovesgshp

Thanks Gterr.
With the underfloor heating, are you reducing the room temp by 1-2degrees overnight and then again during the day, or the flow temp in the pump control?
Also change the pasteuerisation to every 30 days, once a week is not really required, unless you use very little hot water.

gterr

Geotherm wrote: »

Thanks Gterr.
With the underfloor heating, are you reducing the room temp by 1-2degrees overnight and then again during the day, or the flow temp in the pump control?
Also change the pasteuerisation to every 30 days, once a week is not really required, unless you use very little hot water.

Lounge target temp 19 C overnight, 20 C 7.30am to 9.30am, 19 C 9.30am to 2.30pm, 21 C 2.30pm to 10.30pm. This is programmed using the timer/stat on the wall. I don't adjust anything at the pump. At this time of year it doesn't reach the 21 C target unless we also light the woodburner. As of 4pm today it's managed to get to 20 C and is still trying to get that final 1 degree. I don't think it will manage it.

Similarly, kitchen is programmed to be 19 C overnight, 20 C morning, 19 C from 9.30am to 2.30pm, 20 C from 2.30pm to 10.30pm. It does usually manage to achieve this, but takes at least 2 hours to achieve the 1 degree raise.

Dining room figures: 18.5 C/19.5 C/18.5 C/19.5 C. Rarely, if ever, manages to reach 19.5 C unless we open a door and give it some warmth from the stove. The dining room has the staircase off it, so is effectively open-plan with the upstairs.

Pasteurisatrion: it is set to do this once every 7 days, in theory. But it seems a bit idiosyncratic. I will check settings and reduce it to once every 30 days as you suggest. What was happening this morning do you think, with the elec heater on all that time, and the hot water heated above 60 C??

Oh yes: some of the flow indicators on the U/F coils have rusty red water in them - so much so that it's quite hard to see where the flow level is.

Outside temp indicator has indicated between 1 C and 3 C today, but the ice has never gone from the roads and the patio today.

Cheers

lovesgshp

Thanks, I think I can now see what is happening with the UFH. The timer/stat is shutting off the heat supply from the pump therefore letting the floor mass cool too much. Therefore you are making the pump work harder to reheat the room, increasing the running times and probably the electric heater is cutting in to help. To raise a floor temperature does take some time, anything up to 24 hrs between a few degrees.
The normal "flow temperature" maximum reduction is 1C for UFH or up to 4C for radiators.
As to why the DHW went so high, I have no answer at the moment.

gterr

How would it be if I chose one room temperature and stuck with it for a 24 hour period? Could this be a different temperature for each zone (i.e. for each room)?

lovesgshp

It would be a good idea to try it out, as it could be the same as when you turned the radiator timer off. It is trial and error at the moment, as you seem to have so many timers and stats!!!

gterr

Geotherm wrote: »

It would be a good idea to try it out, as it could be the same as when you turned the radiator timer off. It is trial and error at the moment, as you seem to have so many timers and stats!!!

Yes, and I wonder why I've been supplied with all these timers and stats if I wasn't meant to use them!!

I will set the following constant temps for the U/F:
Lounge 21 C
Dining Room 20 C
Kitchen 20 C
Downstairs bedroom 18 C
Everywhere else 15 C.

Is this OK? It will mean that the warm water going to the lounge will pass through concrete in the hallway etc. which is at a lower temp. I guess this is inevitable, and usual?

I am a bit concerned about the "Room Temperature" setting on the pump. Currently set at 19 C. Will this conflict with the room stats?

Oh yes, and the rad timer is still off. Do you want me to do anything with this? (We can cope OK with chilly rooms upstairs if necessary).

Cheers

lovesgshp

Turn the room sensor influence off for now, and let's see what effect the change has on running times and heat levels. I must admit, that I have never known so many timers/stats etc on a geothermal system!
Leave the rad timer off for the moment

gterr

Geotherm wrote: »

Turn the room sensor influence off for now, and let's see what effect the change has on running times and heat levels. I must admit, that I have never known so many timers/stats etc on a geothermal system!
Leave the rad timer off for the moment

All done.
Meter reading taken.
Will repart back tomorrow morning and tomorrow evening (or more often if you wish).

Thanks again for all your time (everyone!)
Big party here if we get this sorted out!

gterr

Good morning!

Update:
After the adjustments yesterday evening all the downstairs rooms with U/F coils came to temperature remarkably quickly - with the exception of the dining room. This room - open plan with the kitchen and having the stairs, so open-plan with upstairs too - refused to come up to 20 C, and still hadn't made it by this morning.

I heard some of the other stats clicking on and off from time to time during the evening. Have taken meter readings this morning: summary below. I think economy was spoiled by this didning room zone asking for heat the whole time.

This morning I have reduced the dining room stat to 19 C. It is happily maintaining this temp. The pump's fan, compressor, heating water and hot water are all off just at the moment. No coils open. No sign of yesterday's electric aux heater coming on. It is, however, milder here this morning: 4 C and raining.

Will report back this evening.

Meter readings:

5/12/2012 5pm 3070
Adjusted U/F timer stats – no back-off 5pm.
Reduced Room temp influence to 0 5.30pm
Reduced pasteurisation interval to 27 days 5.30pm
5/12/2012 7pm 3077
5/12/2012 10pm 3083 (51 units in last 24h, 1 degree outside)
6/12/2012 8am 3103 (4 degrees outside)