Problem heating system

[Hypnos99]

Whe have a newish build 3 story townhouse with the boiler downstairs in the kitchen & a hot water cylinder on the top floor.

The problem is that at night a pump starts up on the top floor despite nothing happening with the boiler downstairs.
This happens 3 or 4 times an hour & can go on for 10 mins each time.

The noise wakes us up & the only way to stop it is to.switch off the power to the boiler in the kitchen which means the clock resets & has to be reprogrammed each day.

The system is covered by British gas who state that's how the system works & there is nothing that can be done.

Other than replacing the system is there anything else we can do?

 

[oldbuffer]

1. What make and model of boiler is it?
2. Could be:
2.1 Boiler firing up in ECO mode to provide quicker hot water.
2.2 Boiler firing as a frost protection measure.
3. Wouldn't altogether rely on British Gas to know what is happening.

 

[Hypnos99]

Thanks.
It's a potterton promax sl
It does this a lot at night. There are no controls other than a reset switch

 

[Rodders53]

Pictures of the HW cylinder and especially this pump - general views and closer ups showing make and model plates if possible.

Picture of other controls :
isolator and programmer for the CH in kitchen
room thermostats
stuff in the HW tank cupboard, or elsewhere, such as motorised valves

 

[Hypnos99]

Do these help?

 

[Rodders53]

Getting there.

You have two motorised valves, one for HW the other for CH.
A red CH expansion vessel and a white potable EV for the HW cylinder.
The HW cylinder thermostat is set for a scaldingly hot 65C
The Grundfos is the circulating pump for the boiler/heating.

Nothing there that should cause the Grundfos to randomly start. Assuming both CH and HW on the programmer are OFF overnight.

Other expert plumbers and heating techs are required methinks.

 

[Hypnos99]

Thanks. Yes the hw is scalding out of the taps. What should it be set as?

 

[omph]

Thanks. Yes the hw is scalding out of the taps. What should it be set as?

55c should be more than enough. You can get a temp sensor to gauge how hot the water is on the tap and adjust based on that. The reason for heating the water to this temp is to ensure legionella is killed off.

When does your hw cylinder heating cycle run ? usually it is at night.

 

[Hypnos99]

It was set to an hour at 6am & 30 mins at 4pm. With switching the power off it's not set & we just do it manually now.

 

[omph]

What time at night does the noise start ? and is it always the same time ? And what is your thermostat for heating to set at ?

 

[Hypnos99]

We notice the noise around 10 pm when we got to bed & it continues for hours.
The heating is set for 18 but it's switched off when we got to bed.

 

[omph]

Can you turn off the heating thermostat before going to bed ?
Your best bet is it identify when that noise is on vs off. If it turns on with heating or when the cylinder is recharging then that gives you good diagnositic insight.
If its heating, then you need to take a look at the thermostat. If its the HW cylinder, turn down the temp to 55c. 65c is very high and the thermostat will be calling more regularly for heat to maintain said temp.

If it is "normal" operation, then get some rockwool sound insulation slabs and install them in the joists or where ever the noise is coming from. That should dampen or eliminate the noise. Alternatively, you could get a quieter pump fitted or try lowering the pump speed.

 

[Hypnos99]

Thanks. I'll make sure the thermostat is off & see if that makes a difference & I've turned the water temp down.

 

[omph]

Thanks. I'll make sure the thermostat is off & see if that makes a difference & I've turned the water temp down.

Do you also have this issue in summer or when its warmer ?

 

[Hypnos99]

Yes. Initially we thought the noise was some night maintenance work but once that stopped I started looking for the source.