Grundfos pump question

[chrysagon]

Hi All.

My system is open vented using an Ideal Mexico RS40 boiler. The pump is a Grundfos UPS 15-45x18 (model A) and is the second one since the system was installed. I'm suspecting the pump has a problem as the full system never gets hot only some radiators, top floor, get hot apart from the living room and, occasionally the hall one, downstairs, get hot. I've removed all the radiators, flushed them clean and checked flow from the pipes so I'm 99% sure there are no blockages. Air is a problem but eventually it bleeds out. Also when I bleed the pump, if there is air in the system, it does escape but so does a lot of water - is this normal ? I read in one of the posts if you get a lot of water from the bleed screw then the pump bearings could be shot. The system has also had x400 through it, left it in for about a month.
I had a BG engineer to look at it before Christmas but he couldn't find the problem and recommended a power flush at 500 quid ( yeah, right!)
Any help, suggestions greatfully received.

Cheers Chas.

 

[hiretools]

Hi All.

My system is open vented using an Ideal Mexico RS40 boiler. The pump is a Grundfos UPS 15-45x18 (model A) and is the second one since the system was installed. I'm suspecting the pump has a problem as the full system never gets hot only some radiators, top floor, get hot apart from the living room and, occasionally the hall one, downstairs, get hot. I've removed all the radiators, flushed them clean and checked flow from the pipes so I'm 99% sure there are no blockages. Air is a problem but eventually it bleeds out. Also when I bleed the pump, if there is air in the system, it does escape but so does a lot of water - is this normal ? I read in one of the posts if you get a lot of water from the bleed screw then the pump bearings could be shot. The system has also had x400 through it, left it in for about a month.
I had a BG engineer to look at it before Christmas but he couldn't find the problem and recommended a power flush at 500 quid ( yeah, right!)
Any help, suggestions greatfully received.

Cheers Chas.

hello im not a plumber yet but u have a similar set up to mine do u have a motorised valve on it if so wot is it 2 way or 3 by that i mean how many pipes attach to it if its 3 u might be better off with a grundfos 3 speed ups 15-50 18 or 15-60 model m8 hope it helps let me know .

 

[oldplumber]

call in a plumber to check your system, did you read the x400 instructions, normally you shouldnt leave any cleanser etc in for more than 2 weeksit rots your system etc!!!! you need to have your system checked to see if your neatral node is correct and air isnt being sucked in , then getr your engineer to balance your system properly.

 

[chrysagon]

Hiretools
Thanks for the reply.

No, I dont have a motorised valve but there are two manual valves after the pump which allows me to select hw or ch or both.
The pump is a 3 speed already but it's the same result at all speeds.
I have a BG maintenance contract but I wanted to know if the pump could possibly be bad before I call them out again.

cheers
Chas

Oldplumber,

Also, thanks for your advice.

I left the x400 in on the advice of the BG plumber but it hasn't made any difference. I have a maintenance contract with BG so I'm going to get them in to change the pump, dont know if that's the problem but I want something for my money. Can't say i'm overly impressed with their fault finding capability though but I'm not shelling out more readies for another plumber when they should be solving the problem.
Not being a plumber myself, what's the Neatral node you mentioned, i've always had to bleed air from the system and wondered if it was getting in somewhere.

Cheers
Chas

 

[Carlisle Lucas]

Hello from Narragansett, Rhode Island!

I have an Embassy Industries "Cosmogas Axia 29E" combi boiler in my house. These types of boilers are not common here in the U.S. and I have had problems finding plumbers willing to service my boiler so I have had to learn the hard way..... I replaced the expansion tank today and the safety relief valve, which was a pretty straightforward job but after repressurizing the system I developed a leak from the square valve stem projecting from the bronze housing on the GRUNDFOS circulator pump. I am guessing that this is a bleed valve. It looks like the square stem of a hose bib valve. After removing the guard which holds the valve in position and fiddling with it for a while in an attempt to stop the leak I turned the boiler back on and soon thereafter it stopped leaking. When I turn this square valve stem with a wrench I can hear the water starting to flow through the system. It seems like the the more I crank it clockwise the hotter the heat pipes become. I think it's working properly at the moment but I wonder if anyone could enlighten me as to what is actually going on here. I couldn't find any technical manuals on this pump online. Any advice or insight will be greatly appreciated.

Carl

 

[SafeGasInstall]

begin with turning off the rads which are getting hot ,and i believe is a pipping issue there ...very likely is that you need a valv fitted on your hot water return from your cylinder as cylinder may have take away all the heat !
or it could be that you have a air lock ,or faulty valves .or bocked return pipe
forget about bg ,just call local plumber will cost you less and will get it sort it out quicker then 500 for power flush and then 300 for magnaclean

 

[doitmyself]

Hello from Narragansett, Rhode Island!

This is a UK based forum. You will get more appropriate help if you contact Heating Help , which is USA based.

 

[dontknowitall]

I'm wondering if the pump is seized. (You'll need a towel for this job ...)

1. Isolate the electricity from the pump.
2. Remove the large screw from the front of the pump.
3. With a 3mm screw, try turning the pump.
4a. If it turns freely and a dribble of water is coming out then it's working.
4b. If it's difficult to turn then it's probably seized and will need replacing.

The classic symptons of a pump failing are hot radiators upstairs and cold radiators downstairs. Depending on the pipework, not all the ones upstairs will be hot and not all the ones downstairs will be cold.