Old system in new house poor hot water temp

[scoobydo123]

Update,

Decided to drain system, F&E tank looked reasonable in respect to colour (thin layer of oxidated water at the bottom). I used my wet vac to empty header tank and drained system from the 2 drain points on the Gnd floor (on on the rad circuit the other by the boiler just under pump).

Filled system back up with x800 via the header tank. System filled fine and all air bled out fine. Brought the system back on line and took it up to midway temp followed by increase in pump from the current setting of 1 to 3. However this resulted in pumping over (also setting 2 causes this). When it pumped over the previously clean water in the header tank then took on a brown rusty appearance. I have left the system overnight on 3 on the stat but 1 on the pump and returned this morning and increased to MAX on boiler stat. All rads getting piping hot, flow and return on cylinder also nice and hot but still overpumps if set above 1.


Boiler is floor mounted with cylinder about 400mm above in the kitchen with the F&E mounted in the loft on the other side of the propery so quite a lot of head height and pipe length. Do you think I have a sludged/partial blockage or just a poorly designed system. Given that all rads are getting hot even though "only" on pump speed 1 should I worry. Have been around with a magnet on pipework around boiler and it has no attraction or would I find this elsewhere in the system if I had a blockage (Do i need to follow feed pipe goes through upstairs cupboard then dissapears under the floor and check there).


Tks

 

[Nige F]

I think its a cytrol valve, its probably failed if your hot water isint hot enough, have you checked that the expansion tank in the loft has water in it ?

It IS a cyltrol valve leave it all as it is - until the summer

 

[doitall]

Normal problem if it didn't do it before is a blocked cold feed.

 

[scoobydo123]

Not worried about the cytrol valve as HW performance is fine since bleeding the cylinder. CH also seems fine all rads very hot only just the pumping over on antyhing but setting 1 on the pump that appears to be an issue. Only completed on the house on the 20th so not sure if it has always been an issue. The gooseneck over the top of the F&E tank is only around 25cm above the water level could this be the issue? Failing that is it a case of getting the floor up to cut the dodgy section out or should I be grateful that the system appears to be working fine (ie all rads hot and HW on the gravity side fine)
tks

 

[doitall]

The problem will be between where the cold feed joins the system and the header tank.

Of course it could be connected wrong in the first place.

Perhaps a pic showing the pump and fittings around it, and one showing the connections on the side of the cylinder.

 

[scoobydo123]

Will get some pictures for you all to have a look at but it could be that it is buried under the floor seeing that the boiler & cylinder are on the gnd flr.

tks

 

[doitall]

Unlikely.

See if you can trace the cold feed pipe from the header tank

 

[scoobydo123]

Boiler is on the gnd and header obviously in the loft but on opposing sides of the property. System is woking fine( as far as I can tell) apart from that it needs to be on pump setting 1 (which it was already set to when I got he property on the 20th of this month).

 

[doitall]

If it works fine on 1 leave it on 1, but keep an eye on the tank.

 

[scoobydo123]

Will do

Thanks

 

[scoobydo123]

Good news and 1 question

Had the boiler serviced and gas safety check boiler is running @86% efficiency, just need to get a flue guard.

X800 has now been drained out and refilled with plain tap water, got the cytrol valve working as well. Still got the pumping over on anything above 1 so started to have a look around at the pipework. I have found a kink (not totally crushed) in the cold water feed from the F&E tank (see photo sorry for poor quality).The pipe is 15mm and the kink is around 3M from the tank. I have also found where it tees into the heating circuit (still 15mm)but no magnetic attraction.

Do you think this kink could cause my pumping over? Or is it just generally a poor system design 15mm not going to 22mm (although from the boiler is 22mm). However system does seem to perform ok but I do think it may be drawing in air perhaps due to kink

Untitled

• scoobydo123
• 1 Jan 2011
• 1

 

[tamz]

house that has a Potterton kingfisher 2 free standing boiler


Had the boiler serviced and gas safety check boiler is running @86% efficiency

Some people will believe anything

 

[ajrobb]

As there is a manual bleed valve that seemed to fix the DHW, I wonder if an automatic air vent would be useful.

 

[scoobydo123]

Hi dont appear to have any issue with DHW. Issue I have is that the pump can only be run on 1, haven't checked to see if this gives flow & return temps within spec as have no means of balancing rads as yet as I dare not touch any of the valves as I know I will get leaky spindles (got TRV and new lockshields on order).

Only issue I seem to have is the pumping over on anything but 1. This is why I have had the floor up to try and find if I had corrosion/magnetite build up. This is when I found the damaged pipe.

Have also ordered a programmable room stat to try and get a bit more control over the system (ie have boiler come on early morning to heat the cylinder but have room stat low and the let the program on the roomstat kick in after say an hour).

 

[ajrobb]

Hi dont appear to have any issue with DHW.

But your original post says otherwise:

DHW not that hot.

I appreciate that manually bleeding the coil has currently fixed the original problem. I was offering a suggestion to prevent the original problem recurring. Maybe a plumber can say if it is barking mad or not....

HNY