The old Rads warming up when HW is on (and CH is off) issue

[MikeJep]

Hi,

Excuse my posting but I'm new to all this. We've recently had a Smiths plinth heater installed (by our Kitchen Fitter!) onto our CH. We couldn't get it working until he balanced the rads by turning them down a bit.

I don't know what else he touched but we are now suffering a few warm rads upstairs when just the HW is on. I can't seem to see a diverter valve anywhere on the system. The little silver box in the picture has no cable supply. The layout is at least 20 years old, although the potterton boiler has been in about 4 years.

Any ideas? I hope you can see the image below of the setup. Motor on left is for CH and pipe to left is cold when rads warm. Let me know if you need any further info.

Cheers

Mike

Untitled

• MikeJep
• 29 Jul 2008
• 1

 

[Softus]

It's possible that your kitchen fitter has piped the plinth heater into the wrong circuit, and that you're getting reverse circulation through some rads.

Where is the silver box?

What is the blue thing that appears to be a divertor?

Where does the pipe go that comes out of the top of the blue thing?

Where does the pipe go that comes out of the right of the blue thing?

What is the programmer?

Did the kitchen fitter drain the system?

 

[namsag]

.The BLUE THING is a pump.
On this sort of circuit there is a anti gravity(non return) valve to stop rads heating up when just the water is on.
So if he has just used pipes that where already there for plinth heater and not teed in anywhere else the chances are while draining it the valve has got some carp into stopping it reseating properly.
They are sometimes built into the blue pump sometimes seperate.
This is providing he did not alter where he teed in

 

[MikeJep]

Hi Softus,

To be honest, the fitter got his 'plumber' to drain the system, remove a rad and put flexi tails on the old pipework for the new plinth heater whilst the kitchen was being refitted. Oddly enough I had to seriously bleed most of the rads afterwards which brings into doubt the Plumber's competence. There was no sign of any anti corrosion bottle in the skip afterwards either...

In response to your questions:

The only small (used to be silver) box I can see is to the left of the left hand motor. I don't know what it is.

The blue thing is...(I assume) a pump for the hot water (turned to low see if it sorted the problem).

On top of the blue pump, the 15mm pipe goes upstairs somewhere.. (to the hot water tank?) and is red hot when HW is on.

To the right of the blue pump, the 22mm pipe goes through the wall to the boiler cupboard and is red hot when HW is on.

The programmer is a Horstmann Channel Plus XL Model H27.

As above, the system was only drained at the time of fitting the flexi tails.

Thanks for your comments.

 

[MikeJep]

Hi Namsag,

Thanks for the info.

Would the Anti gravity device possibly be the small box to the left of the central heating pump?

Would the reseating issue be able to be resolved by flushing the system or something? Is it something the 'plumber' could have avoided (if you know where I'm going!)

Cheers

Mike

.The BLUE THING is a pump.
On this sort of circuit there is a anti gravity(non return) valve to stop rads heating up when just the water is on.
So if he has just used pipes that where already there for plinth heater and not teed in anywhere else the chances are while draining it the valve has got some carp into stopping it reseating properly.
They are sometimes built into the blue pump sometimes seperate.
This is providing he did not alter where he teed in

 

[Softus]

The only small (used to be silver) box I can see is to the left of the left hand motor. I don't know what it is.

Nor me. But if it's a valve then it must be always open or something wouldn't work at all.

The blue thing is...(I assume) a pump for the hot water

It seems unlikely that two pumps would be installed in series without at least one of them cavitating.

Also, the blue thing has three water connections.

Does it vibrate? Does it have a spindle? Can you find out under what circumstances power is supplied to it?

(turned to low see if it sorted the problem).

Please explain more about this "turned to low" business.

On top of the blue pump, the 15mm pipe goes upstairs somewhere.. (to the hot water tank?) and is red hot when HW is on.

To the right of the blue pump, the 22mm pipe goes through the wall to the boiler cupboard and is red hot when HW is on.

So, at the moment, that 15mm pipe would appear to be a gravity flow to the DHW cylinder, assisted by the pump when the heating is on.

The programmer is a Horstmann Channel Plus XL Model H27.

And is it configured in gravity or fully pumped mode?

If you remove the programmer (with its power supply off), can you identify the "HW ON" and "CH ON" connections and find out where the wires go?

 

[namsag]

Confirmed then muck in a anti gravity valve(non return)
To lefthand side of grey pump the lump of a fitting there does it have an arrow on it

 

[MikeJep]

Gents,

I'm not at home at the moment, so will have to take a closer look at the mysterious box and the programmer tonight.

The blue pump does have a spindle and powers up when the HW is on. The knob on the front has 3 settings for different speeds.

Just out of interest - the lefthand grey pump and box do not get warm at all when the HW is on.

Cheers


Mike

 

[namsag]

Ignore softus it is a pump and it was a way they done it years ago and is still avialable as a grunfoss pump plan.
Yeah that little box fitting maybe a valve its hard to see from the picture .
Not something that could be avoided as such its just bad luck that muck floating about in system has lodged in the wrong place .
Try running the heating for a bit and see if it shifts.
This system is in effect a fully pumped system but not in the conventional way

 

[lagunaglen]

The "angled top" box to left of pump,seen one before,also near a pump, which i had to change. When i refilled had a few probs so i carefully undid the screws on the top and lifted the lid, got a gush of water out and seemed to clear the problem i was having.
I ws very careful and just lifted it a little at a time.

 

[having_a_gas]

What is the blue thing that appears to be a divertor?
quote]

An SMC controller pump - runs for DHW circuit.

 

[Softus]

What is the blue thing that appears to be a divertor?

An SMC controller pump - runs for DHW circuit.

Ah, OK. Thanks, having_a_go.

Ignore softus it is a pump and it was a way they done it years ago

By all means ignore me if you want to, but I didn't say that it wasn't a pump - I asked what it was.

...and is still avialable as a grunfoss pump plan.

Nope - the Grundfos pump plan has the pumps in parallel, not in series.

 

[namsag]

Your showing your limited knowledge again softas nobody other than you mentioned series or parrallel . What was said is the its available as a pump plan which does exactly same as an old smc configuration .
But then again if you think a pump is a divertor you obviously have not got a clue.

 

[Softus]

Your showing your limited knowledge again softas nobody other than you mentioned series or parrallel.

You mentioned pump plan, which is a parallel pump configuration. You seem to find it very hard to talk about a technical subject without making personal comments.

What was said is the its available as a pump plan which does exactly same as an old smc configuration.

And I've thanked the person who provided that information.

But then again if you think a pump is a divertor you obviously have not got a clue.

Well here's an interesting notion for you:- the whole point of the Grundfos pump plan is to obviate the need for MZVs, and topologically the configuration is the same as one pump and one divertor valve, so it is, in fact, just a divertor.

And nothing you can say about me changes the fact that you made no attempt to name or explain the "SMC" configuration, even for the benefit of the OP.

 

[namsag]

There was no need to explain to the OP as the problem was not either of the pumps . And it was pointed out to the OP that what they affectively had was a fully pumped system . But with a non return (anti gravity ) valve
And no matter how you try and word it it is NOT a divertor its A PUMP pure and simple.
Just consider yourself educated on this matter you may come up against in the future and you will not look stupid infront of a customer saying your divertor is bust