Changing water pump (Grundfos 15-50)

[KurtKebinger]

Need to change water pump, There is what looks to be a shut off valve above and below the pump. Do I need to worry about creating an airlock in the system? Was also considering introducing a central heating treatment to clean the system through. Where do I need to put it in? And are there any recomendations on what type to use and how much?

Thanks

 

[Soggy_weetabix]

Just turn off the valves, remove the pump. Then put a new pump in, undo the valves and job done.

Its easy.

But just in case, heres a few tips...

1 If the valves are 'ball type', they will leak.
2 Gate types may not, and if they do can be repaired.
3 If the valves fail to shut off properly, be prepared for a flood or have a hose on a drain cock so as you may drain the system quickley.
4 The valves may shut and not re-open. Refer to point above so as new valves can be installed with new pump.
5 Will Pump Unions undo? Have club hammer, junior hack saw ready if the valves hold and you cannot undo the unions.

Easy really.

Dave

an airlock may occur if you have to drain the system. see faq to fix. If drained, shove 4.5 litres of fernox mb1 upon refilling, or pour it in the header and pull it through a drain cock

 

[KurtKebinger]

Cheers Dave,

Figured it may be that straight forward but I'm a chippy with no plumbing experience to speak of.
You'll have to excuse me for asking what may be a silly question but when you refer to the different valve types how would I know what I'm looking at? They look like taps although, typically the handles are missing!

 

[swbjackson]

The handles are supposed to be missing to prevent accidental turning off. After turning the valves off place an old towel under the pump and remove the vent screw. The water should dribble out and stop, if it doesn't the valves haven't shut properly. It's a lot easier to get this screw back in than trying to refit a pump when water is peeing everywhere.