Apollo - shuts off and crud on pump

[buckmoy]

Guys - another Thorn Apollo problem thread!

I had some probs a few months ago (boiler banging and auto-off) - a plumber came round and fitted a new pump and 3way valve. Spent about 6 hours with me and charged 200 quid inc parts so I was happy.

All was happy for about 3 months.

Over xmas I noticed a wailing/scraping sound coming from the pump intermitently - when I went to check I noticed limescale-type deposit around the back, where the impellor casing seal is..

Then a couple of the radiators stopped working with CH on.

This moring I tried HW which worked for about 10 mins before banging, then CH which lasted only a minute or so with the boiler fired. Both times there were bubbling sounds coming from the CH overflow tank.

Any ideas? My g/f has put a ban on s*x until I sort this out!

As a secondary question - when the plumb came round originally he went round hammering the thermostatic rad valves with a hammer. Why was he doing this? I am worried this has freed loads of crud to slowly cak my system.

Help

 

[croydoncorgi]

Wailing and scraping suggests solids in your (new) pump. Pity you left it until now.(especially if the girlfriend dislikes the accompaniment / competition! )

I assume he was tapping thermostatic valves to unstick the valve pins - standard practice. Should not have dislodged much from the rads unless he went mad!

If he drained the system to change the pump & valve, did he give it as good flush-out at the same time? Did he check the state of the water that came out of the drain, for black / brown / other contamination? Did the system have inhibitor in it before? Did he put any in? If the answer to any / all of these questions is 'no', then this might account for your present problem.

 

[kevplumb]

This moring I tried HW which worked for about 10 mins before banging, then CH which lasted only a minute or so with the boiler fired. Both times there were bubbling sounds coming from the CH overflow tank.

more than you where mate

listen to cc

 

[buckmoy]

Don't think he drained the system when he put the new pump / valve in - just closed the flow at some point before the pump / valve area.

No inhibitor.

Have found that the limescale / crud is coming from a small leak just above the pump - this is where he had closed the system to fit it.

I guess this means my system is full of crud now. And the guy wasn't committing sabotage when he was hammering my rads - so I will call him up and get some more cash ready...the thing is - will a system power flush (or whatever) solve this problem?

Should I resist if he tries to tell me that the crud has got inside the boiler and that I need a new one?

 

[croydoncorgi]

If the leak is 'above' the pump, chances are it's on the suction side of it. Therefore, when the pump operates, it's probably been drawing IN air rather than leaking water out. Air getting in is a major cause of corrosion and (especially) broken pumps. The pump is lubricated by water. If air gets into the pump bearing on a regular basis there will be metal / metal contact and before long aforesaid wailing and grinding. You must ensure adequate lubrication before wailing and grinding starts!!!

Get the plumber back to dismantle the pump and clean it up. (Simple to do and worth a try, anyway.) Then fix the leak that (presumably) he left after the original repair. Then drain the system properly and check there's no major black / brown contamination in the water. If so, needs a proper flush. Then refill the system and check it out. Replace the pump again if necessary. Ensure corrosion inhibitor is added as final step. More or less what should have been done in the first place, I'm afraid.

Proper flushing will get most contamination out of boiler, rads and pipes. Although an old system will never be completely 'clean' again, it should be perfectly serviceable. If the boiler fires correctly and the only problem is with circulation, then theres no reason to change the boiler. However, an Apollo will be quite old (maybe very old). If you're planning to replace it anyway and especially if you plan to put in a combi instead of the HW cylinder, cold tank etc. make sure you don't invest too much in repairs to the old system: it won't last forever and the Apollo is not very efficient.

It's quite unlikely that there's any significant limescale in the CH water. The deposit around the leak is where water has evaporated and left salts / other dissolved stuff behind. These are not usually the cause of any problem whilst dissolved in the water.