Water not hot after changing Room Thermostat

[Rincewindwiz]

HI All
My room thermostat (Digistat 1) gave up the ghost in the summer so I replaced it with a Digistat+3 (same backplate)
It was fine until recently (it had got colder!) when I noticed that the radiators were not as hot as they used to be and the hot water was not as hot
For example: I can shower using just hot water (no cold required)
The heating is now on , the controller is showing a flame (and has been for ages) but the radiators are only luke warm.
So I am confused as I did not think the room thermostat affected the water temperature!!
But there is a small grey box in the side of the HW tank with wires coming out of it which go into the same collection of wires as the pump wires. So I guess this might be a temperature sensor.
But I cant see anywhere on the digistat3+ to set water temperature nor anywhere on the hot water tank

Any suggestions as to how I get hotter water?

 

[ShaunCorbs]

You should have a timer somewhere as the stat is just for the heating to the rads

 

[Knappers]

Not seen a setup quite like that before

 

[ShaunCorbs]

Thermal store

 

[Rincewindwiz]

The only other timer is on the boiler and that turns on and off when it supposed to. But I dont think the issue is not turning the heat on rather that the water is not hot enough. Must presumably be a temperature control somewhere to stop the water from boiling?
I'll try the boiler 'boost' button (turns it on regardless of the timer) tomorrow and see if that makes a difference.

 

[ShaunCorbs]

It works in reverse to a stnd hot water cylinder so at a guess the right red pump should be on when the store needs heating (should be an arrow point up on the body of the pump)

 

[Rincewindwiz]

Situation much better this morning.
Pipes same temp above and below both pumps (both throbbing nicely)
Red has arrow but it points down?! - IIRC I replaced this pump a few years ago. Did I screw up? It seems to work OK
Hot water back at normal temp
Will check (Again) stat timing and see how things progress thru the day.
Thanks to all who have responded

 

[Basher]

Trusting that the flex hanging from the choc. block on the left of the photo is a temporary arrangement while you investigate! It needs making safe by an enclosure incorporating cable strain relief, and no visible single insulation. But you know all that!

 

[Rincewindwiz]

Trusting that the flex hanging from the choc. block on the left of the photo is a temporary arrangement while you investigate!

Indeed so

 

[ShaunCorbs]

Situation much better this morning.
Pipes same temp above and below both pumps (both throbbing nicely)
Red has arrow but it points down?! - IIRC I replaced this pump a few years ago. Did I screw up? It seems to work OK
Hot water back at normal temp
Will check (Again) stat timing and see how things progress thru the day.
Thanks to all who have responded

That’s the one to the rads ok the green one is from the boiler so when boosting / turning on this one should run

 

[Rincewindwiz]

That’s the one to the rads ok the green one is from the boiler so when boosting / turning on this one should run

So one problem (now resolved) is the timer ono the boiler had got out of sync and was runinng 3 hours early so in the evenings the boiler shut down too early everything shut down too early.
So fixed that but still the water is luke warm. The system ahs been running for a couple of hours - heating on Hot water on.
In respect of the two pumps

• the pipes into and out of the green one are nice and hot - uncomfortable to hold for more than a second or two.
• the pipes into and out of the red one are much cooler. Warm, almost hot but easy to hold onto for extended periods of time.

Radiators are lukewarm. So it looks like red pump feeds the radiators?
Why are hte pipes not hot

That’s the one to the rads ok the green one is from the boiler so when boosting / turning on this one should run

OK so the red pump drives the rads? - Its hot but you can hold onto it no problem
Rads may only be warm 'cos the need bleeding - I'll check

But since the green one is very hot why is there not a tank full of hot water? (Boiler hot water setting has been on for 3 hours) (Both pumps seem to be runing fine)
Sorry - confused

 

[ShaunCorbs]

Correct red pump is rads

Have you always had this problem?

 

[Rincewindwiz]

Correct red pump is rads

Have you always had this problem?

No. System has worked fine for 8+years. It even survived my putting in a new pump.
Started misbehaving some 7 - 10 days ago - long enough after changing the room thermostat so that is, on reflection, unlikely to be related.
Have checked clock; checked on/off settings and all seem fine. Boiler (Ideal Classic NF) thermostat set to 6 (77C - winter setting). seems to fire up when it is supposed to.

I hit the 'Go' button at 15:30 (timer does not kick in until 16:30). Boiler fired up. All good.
At 17:30 both red and green pump pipes are hot - green much hotter than red but red OK (can just about hold it OK; cant hold green). Water from taps is hot but I suspect no volume.
Tried to run a bath and got 6" of hot (but not as hot as it used to be) water before it went tepid.
Previously I could get an entire bath and had to add cold water just to make it bearable.

Just after running the bath, both lights (Hot water and heating) on the boiler control (Dayton) are on but the burners are not alight. (They were alight earlier)

 

[ShaunCorbs]

Sorry to say need to watch what happens to the boiler / green pump as these shouldn’t be turning off at least for 2 hours as it’s got to heat the water up in the cylinder

Try just turning the boiler control on eg green pump should run don’t run the heating or any hot water if you can and see if the boiler stays on

 

[Rincewindwiz]

Sorry to say need to watch what happens to the boiler / green pump as these shouldn’t be turning off at least for 2 hours as it’s got to heat the water up in the cylinder

Try just turning the boiler control on eg green pump should run don’t run the heating or any hot water if you can and see if the boiler stays on

Currently
Boiler control Hot water On Heating Off
Pumps Green On; Red Off
Boiler Not alight
Then after 3 or 4 minutes boiler fired up
Then after another 3 or 4 minutes the boiler went out. Green pump still running
Then again 3 or 4 minutes it must have fired up because as I watched it it then went out again.
So what keeps turing it off?

Got to go out now, Will action any further suggestiosn tomorrow am.
Thanks for your help

 

[ShaunCorbs]

Right that makes sense and that’s good

And how hot would you say the cylinder is about half way

 

[Rincewindwiz]

Right that makes sense and that’s good

And how hot would you say the cylinder is about half way

Currently very hot. The pipe from the red pump enters half way up the tank and its now as hot as its everb neen in hteh last few days. Mostly this is the pipe that is lukewarm (see earlier posts). It is now (20:05) as hot as the pipe from the green pump

And I now have to go out

 

[ShaunCorbs]

If you can leave it running as it is eg just heating the store

 

[Rincewindwiz]

If you can leave it running as it is eg just heating the store

Didn't see this in time and normal heating kicked in (It was seriously cold last night so Im glad!)
I am away for 5 days from this evening so I'll leave heating on its holiday setting (5c) and resume when I get back. (Monday evening). Reluctant ot turn it off altogether as it is supposed to freeze a few tomes over the next few days
Thanks for you help so far

 

[Rincewindwiz]

OK back early. Too cold!
Boiler (hot water) has been running since early this morning (7am) its now 23:00.
Boiler running fine.
Radiators mid warm
Hot water not as hot as it used to be and still only 6" in the bath - actually only 3" I measured it!. Will leave hot water on all night and check again in the morning