Radiators not Heating Up

[Deleted User]

You need to lower the pressure or the boiler pressure relief valve will operate. Sadly, after operation they tend not to re-seal properly due to grit etc from the system. Leaking PRVs result in the need for constant system top ups which leads to increased system corrosion (rust = water + air).

A common cause of high boiler pressure is a faulty expansion vessel. 

housebuyer143

tristanjourney said:

I think radiators and boiler are now working! Thank you all for the helps!

Now I notice the pressure is even higher. It is 2.8 when heating.

Can I just leave it like that? I do plan to ask a gas safe engineer to service the boiler, so I guess they will fix that?

Pressure will always go up when it's in use so that's fine. Just bleeding a fair bit of water out when it's cold to get it between 1-1.5 bar would be ideal 

ThisIsWeird

ashe said:

That boiler is a system boiler based on the product code rather than a combi

Thanks - and blimey.

Does that mean it's dual-purpose, but has been set to 'system', heat-only?

Results for 'Vaillant Ecotec plus' - the name on the boiler - returned 'combi' types, and I thought that was correct, and reinforced by the separate CH and DHW output controls. But once I saw 'power shower', I did wonder...

So, what's happening with this one? Is it a combi being used as a system? Or does it have two separate outputs, one for feeding the hot cylinder, and one for CH? That would be a cracking feature - the DHW always needs way over 65oC, whereas you may want the CH much lower at times.

ThisIsWeird

tristanjourney said:

I think radiators and boiler are now working! Thank you all for the helps!

Now I notice the pressure is even higher. It is 2.8 when heating.

Can I just leave it like that? I do plan to ask a gas safe engineer to service the boiler, so I guess they will fix that?

It's easy to sort, as just explained. You wait until it's fully cold, and then bleed a rad until the pressure drops to, say, 1.2bar.

It might be ok, but as also pointed out, if it hits ~3bar, you may be facing more bills as the safety valve will likely need replacing.

This will be a 'big' service! Hopefully the displayed fault will now be ok as the boiler has warmed up nicely. If the pressure rises significantly when hot, then the EV will need some attention, hopefully just a recharge.

So, if you plan to have a service soonish, then that's fine. But if not, it's easy to lower the pressure a tad.

tristanjourney

Hi all,

I have a follow-up question. Now the radiators all started working.

But I found the radiators in the bathroom is always on/heating, even when the timer is off. I've attached how the radiator in the bathroom looks like.

I don't like the noisy (even not too much) while that radiator is working and boiler seems always working for that (as I can see the radiator symbol is on). I tried to turn the right side valve (the one with a white cap) in clockwise direction and found the sound from radiator is lower but still not completely stopped.





Can I replace the valve to a thermostatic valve? Will it be more efficient and less noisy?

Thank you!

BUFF

That rad was probably installed as a bypass rad. If your current boiler does not have another form of bypass it would not be a good idea to fit a TRV.
It is generally not recommended to have a thermostatic radiator valve in a bathroom (the heat/steam from baths/showers can cause erratic performance) .

However, your CH should not be running unless the programmer is set to "on" or within a "timed" block & the room 'stat is calling for heat.

tristanjourney

BUFF said:

It is generally not recommended to have a thermostatic radiator valve in a bathroom (the heat/steam from baths/showers can cause erratic performance) .

What's the general recommendation for the radiator in a bathroom?

In my last house, I remembered the radiator in the bathroom is controlled by the timer. That is handy because I can control when it start/stop. With my current house, it seems like the radiator in the bathroom is always very hot, even when all other radiators are cold (timer is off).

ThisIsWeird

Do you have a hot cylinder? And heated by the boiler? What are the programmed timings for the DHW? Could this towel rail be coinciding with that?

BUFF

tristanjourney said:

BUFF said:

It is generally not recommended to have a thermostatic radiator valve in a bathroom (the heat/steam from baths/showers can cause erratic performance) .

What's the general recommendation for the radiator in a bathroom?

In my last house, I remembered the radiator in the bathroom is controlled by the timer. That is handy because I can control when it start/stop. With my current house, it seems like the radiator in the bathroom is always very hot, even when all other radiators are cold (timer is off).

A manual valve & lockshield.

As TIW said if you have a hot water cylinder that rad heating up when CH  should not be "on" could be related.

tristanjourney

ThisIsWeird said:

Do you have a hot cylinder? And heated by the boiler? What are the programmed timings for the DHW? Could this towel rail be coinciding with that?

Yes, I have a hot cylinder. I believe the cylinder is heated by the boiler. The system is like this: boiler in the loft, and a cold water tank, a hot water cylinder in the cupboard of the smallest bedroom (together with the timer for both HW and CH).

The programmed timings for HW is completely off. The programmed timings for CH is timed.

I don't know why bathroom radiator is on when HW is off and CH is not in the timed block.