All radiators on one side of apartment cold

[belgianwaffle]

I have a combi boiler with 7 radiators in the apartment. When I turn the heating on, only 4/7 get hot. The remaining 3 are completely cold.

It's as if there's something blocking the flow between radiators 4 and 5. I've bled the radiators (hardly any air came out) and restored the pressure in the boiler.

Most solutions online mention balancing the system via lockshield valves, but my radiators don't have any.

We recently renovated the apartment and moved the radiator in the bathroom (the one closest to the boiler) to a different wall. Could this be related in any way?

Also, when the heating is on, the pressure goes from 1.5 bar to 2.2 or so. Is this normal?

Any help would be much appreciated.

 

[oldbuffer]

I'm not familiar with the valve at the top of your radiator. It appears to be a thermostatic valve. Some of the thermostatic valves sold in the UK have a facility for balancing the system thus avoiding the need for a lock shield valve. Perhaps yours has a similar function.
Try looking up the the TRV you have and see what it can do.

 

[cross thread]

start by turning the one’s that work off to see if it’s air in the pipe work ,turn on the heating to find out

 

[belgianwaffle]

I'm not familiar with the valve at the top of your radiator. It appears to be a thermostatic valve. Some of the thermostatic valves sold in the UK have a facility for balancing the system thus avoiding the need for a lock shield valve. Perhaps yours has a similar function.
Try looking up the the TRV you have and see what it can do.

It's a Danfoss RA 23 mm with notches. I couldn't find much information on it.

The head is a Tado smart TRV.

start by turning the one’s that work off to see if it’s air in the pipe work ,turn on the heating to find out

Tried that. The cold ones remain cold.

 

[cross thread]

Have you removed the heads and checked the pins are moving ?

 

[belgianwaffle]

Have you removed the heads and checked the pins are moving ?

I have. The pins appear to be fine.

What is odd is that, on the working ones, even with the valve closed, the two pipes at the bottom will heat up (but not the radiator itself). The pipes on the other ones are ice cold.

 

[martygturner]

area there any room stats ? Any zone controls ? if not sound like crud block.

 

[belgianwaffle]

area there any room stats ? Any zone controls ? if not sound like crud block.

The only zone controls I have are via the smart TRVs. They are all connected to one wall thermostat that controls the boiler.

 

[martygturner]

I assume you have removed the smart trvs and run the system just to check that they are still working and are linked.

 

[belgianwaffle]

I assume you have removed the smart trvs and run the system just to check that they are still working and are linked.

I have.

 

[martygturner]

So with the trvs unscrewed off all the cold rads was any warmth felt in the pipes leading to the first and last rad cold rad...the one in the lounge and bedroom?

You need to check the flow to the rad...with the system cold add a bit of pressure to the system say 0.5bar, with the trv off the rad bleed the first cold rad that has some warmth going to the pipes until you have say 500ml of water in a jug from the rad. This will at least prove flow.

But it really sounds like a crud up at that first rad with hot pipes and no warm rad.

 

[belgianwaffle]

So with the trvs unscrewed off all the cold rads was any warmth felt in the pipes leading to the first and last rad cold rad...the one in the lounge and bedroom?

Nope, none.

You need to check the flow to the rad...with the system cold add a bit of pressure to the system say 0.5bar, with the trv off the rad bleed the first cold rad that has some warmth going to the pipes until you have say 500ml of water in a jug from the rad. This will at least prove flow.

Did exactly as instructed. Added .5 bar of pressure, removed the TRV from the first cold radiator, bled it until I had about .5l of water in a jug. The water was cold, the pipes too. Checked the boiler - lost about .5 bar of pressure after bleeding.

 

[martygturner]

So you are getting pressure but no flow. Therefore the return at least has a path to the rad. Give all the thermostat housings( the metal of the valve - not the trv itself) a good few sharp tapsas it really sounds like a crud build up at either of the cold radiators at either end of the cold set of rads.

 

[belgianwaffle]

So you are getting pressure but no flow. Therefore the return at least has a path to the rad. Give all the thermostat housings( the metal of the valve - not the trv itself) a good few sharp tapsas it really sounds like a crud build up at either of the cold radiators at either end of the cold set of rads.

I've been tapping like crazy for the past 15 minutes to no avail.

Again, on the working radiators, the pipes coming out of the floor get warm even when the TRV is closed. Is it possible the buildup is elsewhere (between the last hot and the first cold rad)? Also, could it be that some air got trapped in the system when the contractor moved the bathroom radiator?

 

[martygturner]

well yes...if the pipes are warm then thats where the blockage is..in the rad / valve ....1st choice is air and second is crud...would suspect the trv valve is blocked.

If the rad bleeds water what is left the trv valve...