Secondary Return Pump and Check valve Issue

[Chrisdalbs]

Just fitted a 15mm double check valve to secondary return. We had turned off the valves either side of the bronze pump for the last month as without the check valve it was drawing cold water from the bottom of a Megaflo CL250. Anyway, after fitting the check valve, opened valves and turned on pump. Pump didn't do anything. Took apart Wilo SP30 and the impeller disintegrated!! Now I presume this is just down to age (12yrs) and the fact it hadn't been used in a month or so. My question is what should I replace it with - was thinking of a Grundfos UPN 15 50 N Bronze. Would this be okay? Will the extra resistance caused by the 15mm double check valve cause any issues? When I blew through it it was quite hard going?!

Thanks for help,

Chris

 

[Ch4 plumbing]

The above pump would be fine, you don't need a double check valve, a single will suffice.

 

[Chrisdalbs]

Thanks for that - I've already fitted a double - is it likely to cause an issue?

 

[Ch4 plumbing]

Shouldn't do, as long as the pump circulates through the return pipework then it's fine. Most secondary return pipework have very little resistance.

 

[Chrisdalbs]

Is it normal for check valves to be hard to blow through - just don't want to find I keep burning through motors because of the added resistance?!

Thanks for your help...

 

[Ch4 plumbing]

Is it normal for check valves to be hard to blow through - just don't want to find I keep burning through motors because of the added resistance?!

Thanks for your help...

Yes the type you have probably fitted is basically a spring with a plastic ball on the end, it should be fine.

 

[Chrisdalbs]

That sounds like the one - like this (see pic). Are there any cheaper alternatives to the above pump? - I saw on ebay people are selling cheap plastic body pumps as 'alternatives' but looks like a bit of a scam to me - can't see their spec on Grundfos or Milo websites?!

Thank you so much for your help - really appreciate you taking the time..

 

[Killy Bing]

remember when you're blowing into it you're compressing the air inside your mouth and to the check valve as it has a resistance.
as water doesn't compress it pushes through the valve 🙂

 

[Chrisdalbs]

remember when you're blowing into it you're compressing the air inside your mouth and to the check valve as it has a resistance.
as water doesn't compress it pushes through the valve 🙂

Good point - thought it must be something like that... Thanks..

 

[chris watkins]

Hi Chris
Did you check the temperature rating of the check valve you installed ? some are ok but some are not after all they are plastic, rubber & lightweight springs on the inside ?
I would normally install a flap type / swing type non-return but as you are asking about a new circulator I would suggest the use of one of the Grundfos Comforts which have built in non-returns I believe, they are also EuP compliant, which the 15-50 is not.

CHECK & RELIEF VALVES, STRAINERS & DRAIN COCKS

Grundfos Comfort | Grundfos

 

[Chrisdalbs]

Hi again, Finally got the pump removed looks like bearings had gone too!

Anyway, been looking at pumps today and found this one Wilo Star Z Nova. Any thoughts? Stainless impeller sounds good to me and low power consumption. Also can get it on import from Germany for just short of £100! Is this okay for our application? Currently was fitted with Wilo SB30. I think it also includes it's own check valve. Much cheaper than I can get the grundfos comforts...

Thanks for your help...

 

[AWheating]

Hi Chris
Did you check the temperature rating of the check valve you installed ? some are ok but some are not after all they are plastic, rubber & lightweight springs on the inside ?
I would normally install a flap type / swing type non-return but as you are asking about a new circulator I would suggest the use of one of the Grundfos Comforts which have built in non-returns I believe, they are also EuP compliant, which the 15-50 is not.

CHECK & RELIEF VALVES, STRAINERS & DRAIN COCKS

Grundfos Comfort | Grundfos

Chris have you installed a comfort pump on a secondary return? and does the EuP cover secondary returns?

 

[chris watkins]

Chris have you installed a comfort pump on a secondary return? and does the EuP cover secondary returns?

Yes on both counts AW
We installed the AutoAdapt on a guy's system in Essex, that he blagged off Grundfos at one of the show a couple of years ago before it was even on general release. Funny enough he made contact again last week on a different matter & I asked him if it had been alright he said he had not thought about it since as hot water was always at the taps when he needed it. so it must be working OK.
I believe that EuP second lot comes in at the end of this year were even pumps installed in appliances (such as combi's) must have energy efficient pumps installed as replacements, it applies to all pumps even boosters not just circulators.