Boiler and CH problems

[Hugh Jaleak]

I'll hang my hat on the hydraulic explanation in posting nr 67 and 40 years in the water industry and an understanding of Bernoulli,Colebrook White, et al (my research I guess?) but, based on your experience and hydraulic knowledge, please feel free to put forward any logical counter arguments to the "theory" put forward as opposed to a nothing reply which doesn't explain/support any of your interesting statements, which, I think could be the answer to the world water shortage i.e. suck water from no where and discharge into a holding tank

My knowledge is based on experience, having had to deal with the issue a few times. First off as an Apprentice, when the Bosses idea of converting a Gravity HW / Pumped CH system to Fully Pumped in order to try and solve a circulation issue, resulted in a torrent of hot water from the F&E Cistern overflow. Have come across it on several other occasions, usually due to poor system design or blockage issues.

Also IIRC the reason why Vent pipe and Cold Feed must be connected within 150mm of each other if an Air separator is not used.

 

[mcprinter]

Seek advice from the makers. A month? You cannot be serious.

I have had X400 in mine for 3 Weeks as per the Sentinel X400 Instructions. "3-4 Weeks for badly fouled Systems"
Appreciate this wouldn't be practical for a Tradesman or economical for the Customer.

I had quite a bit of sludge in my Rads when removed and flushed.
Added a Magnaclean and filled with X400.
Removed a Rad ready for skimming last Week and the Water was black, so I guess it's doing it's job.

 

[Dereekoo]

My knowledge is based on experience, having had to deal with the issue a few times. First off as an Apprentice, when the Bosses idea of converting a Gravity HW / Pumped CH system to Fully Pumped in order to try and solve a circulation issue, resulted in a torrent of hot water from the F&E Cistern overflow. Have come across it on several other occasions, usually due to poor system design or blockage issues.

Also IIRC the reason why Vent pipe and Cold Feed must be connected within 150mm of each other if an Air separator is not used.

So we are agreed that there must be no undue headloss between vent pipe and cold water feed otherwise over pumping up the vent pipe may occur. Must admit not sure how the 150mm distance was derived as assuming the pipe between them is of "normal" quality the frictional resistance would not be of a high enough value that should cause flow to be diverted up the vent pipe, I assume 6" was a nice figure and kept the chance of a blockage between the two to a minimum. Dont understand why use of an air seperator precludes such a requirement as a blockage is a. blockage?

 

[Hugh Jaleak]

I'm not clever enough to understand the theory behind why it happens, only I've seen it happen, and have learned ways to alleviate the issue. College was over 30 years ago, whilst we may have covered the topic, I only remember the practice to avoid the issue and steps to take is it is happening. The 150mm creates a neutral point to prevent the occurrence. Pumping Over also introduces a lot of fresh water into the system, which also need to be avoided.

Air Separators, such as the 'Myson Aerjec' have 4 connections, Flow in from Boiler, flow out to Pump (Circulator) inlet, Vent and Cold Feed. Air Separators are also a common point for blockages, have cut plenty out in the past.

 

[Dereekoo]

It is not a pump, it is a circulator, it does not PUMP anything at any time

Best tell Grundfos and other pump manufactures their brochures are all designated with the wrong descriptions

And just to help you understand what a pump is here is a dictionary definition for your clarification
"a mechanical device using suction or pressure to raise or move liquids, compress gases, or force air into inflatable objects such as tyres"

 

[ianmcd]

Best tell Grundfos and other pump manufactures their brochures are all designated with the wrong descriptions
View attachment 258254

And just to help you understand what a pump is here is a dictionary definition for your clarification
"a mechanical device using suction or pressure to raise or move liquids, compress gases, or force air into inflatable objects such as tyres"

But they are pumps, Grundfoss make pumps and circulators

 

[Harry Bloomfield]

There's literally no space near my boiler to fit a magnaclean, can I fit it near my hot water cylinder instead?

The filter needs to be fitted just as close to the boiler as you can get it and inline with the return pipe for the central heating, so as to enable it to filter all of the water returning back to the boiler and prevent it blocking the boiler matrix.

 

[Harry Bloomfield]

.