Oops I knocked something

[SteamyTea]

Post up a close up picture of the temperature probe and cable.

[canalsiderenovation]

1 hour ago, SteamyTea said:

Post up a close up picture of the temperature probe and cable.

 

[JohnMo]

Your other issue is the immersion is at the bottom of the cylinder and the probe you are showing isn't at the same elevation. So the immersion and the probe are reading different places in the cylinder, so will see different temperatures.

 

Slip it back together and get on with other stuff.

 

You temperature probe is just a variable resistor, it either reads or it doesn't. It's pretty black and white. 

 

As @JamesPa says hold it in place with some insulation, it will read more realistically, as you don't get cool air drawn into the cavity.

[SteamyTea]

Yes, looks like a thermistor (thermal resistor).

These are dirt cheap components, just a case of finding on with the right temperature/resistance scale if you want to replace it.  Thermistors are generally reliable.

It does not look damaged though, so is it possible that the connection at the other end is loose.

[BotusBuild]

14 hours ago, canalsiderenovation said:

Like this

Yes

[canalsiderenovation]

4 minutes ago, BotusBuild said:

Yes

Thanks I'll do this today with the insulation.

 

We will get it serviced this week anyway, probably long overdue. Meanwhile the cupboard is now empty of mops, buckets and other crap!

[BotusBuild]

It's worth doing the cup of water test to check the sensor is reading roughly the same as a thermometer.

 

Replacement of this, should it have failed is cheap and easy to do.

 

But, insert that insulation, and go do something else for a few hours/days and let it all settle down.

 

The service will do no harm, just don't let them knock anything 😆

[canalsiderenovation]

3 hours ago, BotusBuild said:

But, insert that insulation, and go do something else for a few hours/days and let it all settle down.

 

The service will do no harm, just don't let them knock anything 😆

 

Did this late last night with the insulation and today everything's back to normal! Phew.... still going to get it serviced. Think it's around £150 plus vat, but will ring round a few places first.

[sharpener]

18 hours ago, canalsiderenovation said:

Quick question should the black needle be above the red? I'm sure i read it should be.

 

How do I adjust that?

 

 

Not exactly. The black needle shows actual system water pressure, 1.25 bar might be a bit low depending on the instructions for your particular HP.

The red needle is an aide memoire, you set it by hand to where the black needle is so you can see if the pressure falls subsequently. If this was set correctly then you have lost 0.25 bar since this was done. You may have a slow leak somewhere. You may need to top it up by opening the two black valves slightly until it is the black needle is correct.

[Nickfromwales]

14 minutes ago, sharpener said:

You may have a slow leak somewhere

 

4 hours ago, canalsiderenovation said:

We will get it serviced this week anyway, probably long overdue

If the pressure hasn't been topped up in a long time (or ever?) by the OP, then it defo doesn't have a leak!!

 

Heating systems have a corrosion happening somewhere, a little over a long time, and this process creates nitrogen (iirc) gas which arrives at the automatic air vents, aka bottle vents, and that gets released as 'air'; there is where a little pressure goes over time. Even with inhibitors / chemical treatments, this happens over time. Other causes can be a tiny leak which happens when the system heats up, and the water just evaporates vs a drip being evident. Again, to be completely expected over the number of joints, system size etc. Relax .

 

Topping this back up to 2 bar is ample....do NOT exceed this is the pressure relief valve(s) will be set to open and evacuate at 3 bar. Normal operating pressure for the majority of heating arrangements is 1.5 bar (filled / checked when the system is cold as heat causes the water to expand and that makes the reading rise / fall slightly).

 

On the braided sliver flexi loop, do you have a black tap both ends or just one at one end? 90^o to the pipe direction is fully off, and inline with the pipe is fully open, these are 1/4 turn taps a-la a washing machine tap. If both are closed, as they should be during normal service, then open one fully, then open the other VERY gradually until you hear water flowing. Watch the gauge as the pressure will then start to climb. Get to 1.5-2 bar and then close both taps (make sure you FULLY close them), and check again in 3-6 months. You can move the red needle to where the system pressure was set to, and then you can use that as a reference for how long and by how much the system depressurises.

 

This is not a fault, and is routine maintenance of any sealed and pressurised heating system.

[JohnMo]

23 minutes ago, sharpener said:

You may have a slow leak somewhere

Or a slightly less alarming version, the air in the water when first filled has released and the water now occupies slightly less volume, so pressure is slightly lower.

[SteamyTea]

5 minutes ago, JohnMo said:

Or a slightly less alarming version, the air in the water when first filled has released and the water now occupies slightly less volume, so pressure is slightly lower.

Yes, that is the most likely.

 

[JamesPa]

Just to add to the above, the pressure registered on the gauge may be different, when the pump is running, to the pressure registered by the heat pump due to dynamic resistance in the system.  If the difference slowly increases it might indicate that the magnetic filter needs clearing.

[sharpener]

1 hour ago, JamesPa said:

Just to add to the above, the pressure registered on the gauge may be different, when the pump is running, to the pressure registered by the heat pump due to dynamic resistance in the system.  If the difference slowly increases it might indicate that the magnetic filter needs clearing.

 

Agreement between the gauge and the HP control panel depends on siting of the sensor wrt the internal pump in the outdoor unit.

 

On the Vaillants the pressure sensor is on the suction side so what looks like adequate static pressure when off turns into not enough when pump is running.

 

Not helped by my installers leaving the EV pressurised to the factory setting of 3 bar, which is too high for an HP and means it was not doing anything.