Search the forum,

How to diagnose the cause of pump over

Discuss How to diagnose the cause of pump over in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Status
Not open for further replies.
preece

preece

Messages
3
Recently my CH system is getting Pump Over, but I unsure how to figure out the cause.

1. Seven minutes after switching on, hot water pours through the vent into the CH header tank.
( Nb. the pouring is like a tap turned on ).
2. This happens with either water & heating, or just water.
3. The system has hardly been touched for 30 years.

I'm thinking I must have a blockage and the pump is forcing water up the expansion pipe.

But I would also like to be sure there is no other possible cause. If it is a blockage how would I locate and fix.

Also to help my understanding, what causes the pump to switch on - is it triggered by a thermostat in the boiler ?

Thanks for any help,
Tim
 
Check the ball valve in the feed/expansion tank isn't leaking, i.e. the level stays below the overflow to the outside at all times.

Otherwise, as you surmise, it is almost certainly a partial blockage (of magnetite) in the section between the vent pipe and the rest of the system. The 7 minute delay will be the time needed for all the water in the system to have warmed up and expanded to the point that the pump over can start.

Discuss with your plumber the pros and cons of power-flushing vs a more surgical approach. 30+ year old systems that have been neglected are often rather fragile and a full power-flush can be the final straw.
 
Gasmk1 said:
possibly a blocked cold feed
Click to expand...

Yea I read that blocked cold feed could be the cause, but I can't understand why a blocked cold feed would cause the hot water to gush out of the vent when the pump kicks in.

Presumably the cold feed here means the cold pipe as it leaves the f&e tank, so a blocked cold feed would simply prevent the CH system from refilling.

Tim
 
It will be also down to where the pump is in relation to the feed and vent . Locate the feed and vent and run a magnet over it , if its blocked with magnetite it will stick
 
The cold feed is also where the heating water expands up when your heating and hot water is on. If this is blocked then it goes up and over the expansion pipe.
Check with a magnet where the cold feed tees into the system.
 
I really don't really understand how it could just be a cold feed blockage. If it was due to water expansion then I would only expect a small amount of overflow, not the large amount of gushing water that I actually see.

I suppose if it's often the case that blockage occurs where the cold feed tees into the system, then the system flow itself might have become blocked ?

I'll try magnets.

Tim
 
Sludge and configuration will do this. Have an experienced engineer take a look and advise because either way its going to cost money mate.
 
Status
Not open for further replies.

Reply to How to diagnose the cause of pump over in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Similar plumbing topics

jamespipe
Plumber recommendation for heat pump HWS installation
Hi, My current hot water system needs to be replaced. Anyone got any suggestions or can recommend any plumbers around Derrimut area that won't rip me off? An office guy recommended me to apply for government rebates and get it installed through timetosave.com.au. How reliable is this...
Replies
6
Views
233
oz-plumber
O
P
Repeated Airlock in Bathroom
Hi, Can anyone advise as to why the cold water to my bathroom keeps airlocking? This originally happened about 12 months ago and has happened 3-4 times since. It’s an upstairs bathroom, fed from a tank in the attic. The tank is about 8 Meters away and feeds a bath, sink and toilet. The tank...
Replies
9
Views
255
Chuck
C
D
Covering shallow sewer pipe under concrete Patio
Hello all, I’m replacing a concrete paving slab patio in the back yard. The original patio used 50mm deep concrete slabs on hardcore & sand. I’m planning to pour a 100mm deep concrete patio on 100mm hardcore. In order to achieve the same final height to line up with the rest of the patio, I...
Replies
5
Views
137
DIwhYdidIstartThis
D
D
Extending outdoor tap and drain
Hello all, I'm would like to extend an existing outside tap to another point in the garden. I'm about to pour a concrete patio and was hoping to run the water line underneath. There are existing drain (and who knows what) pipes running along the same wall so I'm nervous about digging too far...
Replies
5
Views
143
DIwhYdidIstartThis
D
Creating content since 2001. Untold Media.

Newest Plumbing Threads

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock