No heating, pump looks a right old mess!

[Deluks]

Radiators not getting hot, hot water still ok.
Y plan, f&e tank etc
3 bed semi, 7 rads.

The 3 way valve was completely changed in 2016, I think it's also had a new head on it since then. (If not I've got a spare knocking about)

So it might be the valve, but having had a look at the pump, I think I'll replace that first, it looks like it's been leaking for a while.
It's at least 15 years old, possibly more. Definitely in need of a replacement judging by the state of it.

Grundfos Selectric UPS 15/50.

A few Q's

1) What's the best like for like replacement?

2) I will likely be adding about 20 sqm of UFH at some point in the future.
Will probably need to convert to S plan, it it worth factoring this in to my choice of replacement?
(ie, do I need a 'bigger' pump or will the UFH have its own pump which will take care of business)

3) Is it worth upgrading the valves to 'perfect pump valves'?
I could patch up the existing, but they've already got PTFE around the glands so might as well have them out.

4) Is it worth investing in a proper spanner for the pump valves, or try and do it with stilsons.
I'm all for investing in tools if it makes the job easier.

5) what to close off/where to drain from?
I'm assuming...
a) drain out and clean the f&e tank.
b) bung/tie off the cold water tank.
c) drain down using drain cock at the lowest point.

The system is a couple of years overdue for inhibitor, so I'm happy to drain and refill system for peace of mind.
Should I do this twice? Once with system cleaner, and then repeat the process with inhibitor?

Thanks in advance

 

[Deluks]

The other 'dumb' question I should have asked.

Does the fact that hot water is getting from the boiler into the hot water tank mean that the pump definitely hasn't failed? Or can the hot water easily siphon up past a pump that isn't circulating and keep the tank hot.

 

[Harry Bloomfield]

Does the fact that hot water is getting from the boiler into the hot water tank mean that the pump definitely hasn't failed? Or can the hot water easily siphon up past a pump that isn't circulating and keep the tank hot.

With a failed pump, there would be lots of short cycling of the boiler, because it would be unable to get rid of it's heat fast enough.

 

[Deluks]

Ok, having stuck my head in the cupboard and had a fiddle, the pump is still circulating and the spindle turns freely. So it's the valve (again)

But given the state of it, I will be looking to replace it in the near future, so the above questions still stand.

Also, Is it worth picking up a NOS or refurbished like-for-like pump, or get one of the newer ones with bells and whistles? (I favour reliability over efficiency)

 

[lostinthelight]

My Ufh has a separate pump but needs both running wether its on together with the rads or stand alone.