Search results

Not sure of anything ! How would I test for an airlock and overcome the problem ? Would the effect of a blockage not be the same as the TRVs closed i.e. by-pass opens due to the pressure of the pump not going anywhere ?

By-pass was full of crud. This one has a mushroom shaped valve held against it's seat by a spring. Once I had cleaned it out it was easy enough to push with my finger, but the spring was way too strong for me to get the valve to open when I blew into the pipe - No matter how much puff I...

I have checked the by-pass again and now confirm as soon as the hot water reaches the by-pass valve position, it does immediately divert through the by-pass (not after 1 minute) and into the return pipe. Some hot water continues down the flow pipe toward the 1st floor, but the return pipework...

The CD24C has a cyclone on the CH return just before the pump, which then feeds into the main heat exchanger. The fill loop sits between the cyclone and pump. This does mean when I flushed the rads with the flow isolated, the water was traveling down throught the cyclone first (in reverse...

Its an Alpha CD24C. While drained for flushing I removed the DHW heat exchanger (back flushed it while off) and diverter valve as a precaution. The valve in the diverter returned to CH several times ok when I pushed it across to the DHW position. There was no sludge or build-up inside either...

Old pump in Combi was running slow and overheat stat was cutting burner off in DHW and CH. The downstairs rads were cold and upstairs rads just getting warm. New Grundfos pump fitted has restored the DHW but the CH is not improved and boiler cycles. When the CH is turned on, hot water...

Even the upstairs rads are barely getting warm now. Before I changed the pump (which was definately faulty), by shutting the rads upstairs I could at least persuade one downstairs rad to get warm - just. I am going to start a new thread as the problem is now different (though obviously...

I have found the post ^^^^ but it hasn't helped (different prob.) :-( I might start a new post or call an HE, or maybe just turn the CH off !

Ha, I am only being cheapskate because I don't have a job anymore :cry: Anyway I didn't come on here for sympathy, just some advice. Now having bought and fitted a Grundfos 15-60, I find the DHW working but the CH still much the same. The boiler is cycling on the CH setting and I think I saw...

Just had a trawl through some plumber supply websites. Screwfix also do a Pegler TC6 pump which has some good user write-ups at 1/2 the Grundfos price. Don't know if it will fit the Grundfos body, anyone help ?

I recognise that the pump fitted in the boiler is a 15-60. But, reading other posts on here indicate that the 60 is a rating for "6m Head" which is not important on a sealed sytem (especialy as my boiler is in the attic anyway). Other than being rated for 5m head, doesn't the 50 pump have the...

OK, friends pump was just the same as mine on "Finger Test". Either they are both good or they are both broke, so no point swapping ! Checked Screwfix website and Wilo pump is £65, only £10 cheaper than Grundfos 15-50. Decided to bite the bullet and went to B&Q as it's nearest and sell both...

I forgot to add; when I took it apart the pump housing was clean inside without any sludge or deposit build-up (probably because the sytem has been flushed so often !).

To be honest the water is always full of black particles. This combi was fitted to an existing system on which the rads are almost 40 years old ! The system has been flushed a few times each time the DHW-heat exchanger clogged up (not surprised I hear you say !). We even added x-400 sludge...

I take it any Grundfos 15-60 pump head can be swapped. However, (as money is very tight !) you have said ^^^^^ any make. Are there brands out there that will definately fit the Grundfos body and any that definately won't (also any to definately avoid) ? When we talk about quality this...

Pump passed the "Finger Test" at setting 3 on workbench. But after re-installing I checked the shaft under the bleed screw; It stopped on setting 1, struggled to get going on 2, and was definately not running as fast as I think it should have on 3. Before I part with the cash price for a new...

I suspect the pump on our combi-boiler may have had it (cold rads. downstairs - system flushed OK recently). I will be removing the pump to check it out per other posts on the forum, but have a couple of questions should it need replaced. It is a Grundfoss UPS 15-60 AO (fitted with auto-vent)...