Rads on ground floor do not work

[Mr Sparkle]

All ground floor rads are not heating up.

On the first floor, two (of four) rads get hot and two are giving low heat.

All Rads in loft area are piping hot

What is the problem?

Background:

1. Boiler is Vailliant 637

2. After switching it on for 1st time, following summer, it had an F75. So Vailliant changed the pump.

3. I've bled the rads, shut the valves/trv on all of rads (except the ground floor rads) and still nothing

Any advice appreciated

 

[terryplumb]

Do you have zonal heating ,thermostats for each floor level ?

 

[Mr Sparkle]

Do you have zonal heating ,thermostats for each floor level ?

No zonal heating

Only one thermostat

 

[terryplumb]

What is the system pressure ?
Is programmer set for domestic hot water and central heating ,or just central heating ?
Has the boiler been used for domestic hot water during summer ,and without any issue ?

 

[Mr Sparkle]

What is the system pressure ?
Is programmer set for domestic hot water and central heating ,or just central heating ?
Has the boiler been used for domestic hot water during summer ,and without any issue ?

I have a system boiler for central heating and unvented cylinder tank for hot water. The heating is controlled by the Nest thermostat.

The pressure is 1.2

Not sure how to adjust programmer for hot water/ central heating

Hot water comes via the unvented cylinder. We have gad no problems with this.

During summer the system boiler was switched completely as we did not use the central heating. It was switched for the first time in about 4 months last week.

The Vailliant t engineer said, switching it off could have caused thr F75 i experienced last week. He replaced the pump.

 

[JohnD]

Turn off all the hot ones. What happens to the cold ones?

 

[terryplumb]

After the pump was replaced,did all radiators heat up whilst engineer was on site ,or didn't he bother to check ?
For some reason you are not getting circulation to all rads ,and need the engineer to revisit .

 

[terryplumb]

Turn off all the hot ones. What happens to the cold ones?

See point 3 in original post John. Apparently no difference.

 

[Mr Sparkle]

After the pump was replaced,did all radiators heat up whilst engineer was on site ,or didn't he bother to check ?
For some reason you are not getting circulation to all rads ,and need the engineer to revisit .

The ground floor rads were not checked.

Today I have

- bled all rads

- drained the system

- stuck wet vac on end of a ground floor rads to remove any possible airlock

- I've shut the valves upper floors and opened the ground floor and still no heat.

The pipe (i suspect it is the flow) which goes under the flooring to feed the ground floor pipes is luke warm.

A bit of research suggests that this could possible be a pump issue.

I guess i will have to contact Vailliant

 

[Mr Sparkle]

Contacted Vailliant:

They won't send an engineer.

They said that they'd be surprised if this is a pump issue as it was just replaced.

According to Valiant, the ground floor rads not working suggests an airlock/ restriction.

Would a power flush sort out the issue? I was thinking of getting one done prior to this issue.

Any other suggestions?

 

[Madrab]

What was the reason given for a new pump and is the system clean?

 

[Mr Sparkle]

What was the reason given for a new pump and is the system clean?

1. Last week the boiler wouldn't fire up/run. It had an F75 error.

2. Vailliant engineer changed the pump and the boiler began running again.

The system was installed about 2 years ago. I know that it had inhibitor.. Can't say whether it had a chemical flush.

But it definitely never had a power flush.

 

[terryplumb]

Unless you are prepared to do some work yourself on radiators / pipework,to establish if there is a blockage then there are only 2 other options. One is to engage an independent plumber to investigate or be more insistent with vaillant ,who I assume have visited as part of a warranty ?

 

[Mr Sparkle]

Unless you are prepared to do some work yourself on radiators / pipework,to establish if there is a blockage then

I will start off with this option.

What should we do? Test? Etc to establish/ clear any possible blockage?

 

[terryplumb]

If TRV,s are fitted (Thermostatic rad valves) to downstairs rads ,check they are not stuck in closed position. It's unlikely with more than one radiator not working,but still worth ruling them out.
You can then drain one radiator ( if necessary remove it) and open one of its valves allowing water to flow out for ten seconds. There should be a strong flow. You will need to keep system pressure topped up whilst doing this. If you can ,mock up a hose connected to rad valve and out to a drain .
Do the same test on the other valve.
If no continual stream of water from valve ,there is a blockage.
Depending on result other rads may need to be tested too.