Realised this week that my boiler was not installed correctly

[sijones]

I have a Potterton Suprima 120L (approx. 120,000 BTU) boiler which has been running for about 5 years. It has never been that great in heating up the rads in my house. I have 21 radiators in total. The boiler never fires for very long. Usually less than 2 minutes.

I decided to read through the installation manual which came with the boilder and discovered two things which were obviously not quite right.

The first issue I spotted was that Potterton recommend using 35mm pipes for the flow and return to within 300mm of the boiler. My installation is using 28mm pipes. My plumber missed this somehow. Although my non-professional view is that if a boiler requires 35mm pipework for the flow and return then why doesn't the manufacturer have 35mm connections on the boiler in the first place. I assume it's because they can share parts with the lower rated boilers in the range. It's stupid if you ask me.

The second issue I spotted is that they also recommend using a commercial pump as domestic pumps are not likely to provide a sufficient flow rate. My pump is a standard Grundfos Alpha domestic pump.

So far I have purchased a Grundfos Magna 25-100 pump. Wow these are expensive bits of kit. Hopefully this will be more than adequate for the job.

Do you think I should get the same plumber back to refit the flow and return using 35mm pipes and install the new pump, while encouraging him to do it for reduced price? Also, is there any other things I should be checking for a system of this size to make sure that everything has been sized correctly.

Kind regards,

Steve

 

[stevetheplumber]

i wouldnt hold your breath on the reduced rate after 5 years

 

[SimonG]

and it's ran ok for 5 years?

 

[sijones]

i wouldnt hold your breath on the reduced rate after 5 years

I'm sure you are right. I guess if there isn't enough money in it for him then he will not be interested.

I've got a large Megaflo installation and I find it difficult to find a good local plumber who is familiar with these installs. I find my existing plumber unreliable to say the least.

 

[sijones]

and it's ran ok for 5 years?

No it has been pretty poor since it was installed as some of the radiator furthest away from the boiler hardly warm up.

 

[dontknowitall]

I'd find a different plumber then - plenty of us about these days!!

BUT ... as ever ...

the trick is finding a good one. If you know of a builder or electrician you can trust then they often will know of a good plumber.

 

[SimonG]

No it has been pretty poor since it was installed as some of the radiator furthest away from the boiler hardly warm up.

So you only have 1 htg zone and the unvented cylinder?

 

[Barry98]

ask on here if anyones near you , theres plenty of good one its whether you can afford us

 

[sijones]

So you only have 1 htg zone and the unvented cylinder?

Yes just the one heating zone and one Megaflo cylinder.

 

[stevetheplumber]

put where you live in a post maybe someone here can give you a price

 

[sijones]

put where you live in a post maybe someone here can give you a price

I'm in Reading, Berkshire.

 

[sheff paul]

I have a Potterton Suprima 120L (approx. 120,000 BTU) boiler which has been running for about 5 years. It has never been that great in heating up the rads in my house. I have 21 radiators in total. The boiler never fires for very long. Usually less than 2 minutes.

I decided to read through the installation manual which came with the boilder and discovered two things which were obviously not quite right.

The first issue I spotted was that Potterton recommend using 35mm pipes for the flow and return to within 300mm of the boiler. My installation is using 28mm pipes. My plumber missed this somehow. Although my non-professional view is that if a boiler requires 35mm pipework for the flow and return then why doesn't the manufacturer have 35mm connections on the boiler in the first place. I assume it's because they can share parts with the lower rated boilers in the range. It's stupid if you ask me.

The second issue I spotted is that they also recommend using a commercial pump as domestic pumps are not likely to provide a sufficient flow rate. My pump is a standard Grundfos Alpha domestic pump.

So far I have purchased a Grundfos Magna 25-100 pump. Wow these are expensive bits of kit. Hopefully this will be more than adequate for the job.

Do you think I should get the same plumber back to refit the flow and return using 35mm pipes and install the new pump, while encouraging him to do it for reduced price? Also, is there any other things I should be checking for a system of this size to make sure that everything has been sized correctly.

Kind regards,

Steve[/QUOTE



Make the heating pressurised (if not already) this will increase the amount of heat copper can carry,if you have got 28mm feeding the s plan,and 28mm pump valves,and a 28mm zone valve feeding heating ,ensure 28 is feeding the first 3 or 4 rads,and as long as the heating load is not over 120000btu,and the rest are piped in 22mm,and not reducing to early to 15mm,it will work

 

[Nat]

Was the system balanced properly when it was installed? Also, its probably a bit late now but have you thought of zoning the heating? Do you need to heat all 21 rads all the time?

 

[sijones]

Make the heating pressurised (if not already) this will increase the amount of heat copper can carry,if you have got 28mm feeding the s plan,and 28mm pump valves,and a 28mm zone valve feeding heating ,ensure 28 is feeding the first 3 or 4 rads,and as long as the heating load is not over 120000btu,and the rest are piped in 22mm,and not reducing to early to 15mm,it will work

It's a sealed system with a pressurise vessel (approx. 35 litres). The s-plan, pump and valves are all on 28mm but everything else is 22mm with microbore to the rads from the 22mm.

 

[sijones]

Was the system balanced properly when it was installed? Also, its probably a bit late now but have you thought of zoning the heating? Do you need to heat all 21 rads all the time?

I don't think it was balanced properly. Although I have tried to do this myself but not with any great success. I could look into zoning as there may be an obvious split in the system.

 

[Blackcatgas]

Id just try the new pump first, balance everything up properly then turn on the heating, sit back,and relax in the comfort and privacy of your own home.

 

[sijones]

Id just try the new pump first, balance everything up properly then turn on the heating, sit back,and relax in the comfort and privacy of your own home.

I initially thought the same but the new pump is 180mm between the connections and this is larger than the one already fitted. Therefore the system will need to be drained and the pump connections redone so I thought that was probably the time to redo the flow and return.

 

[Megaflo-Experts]

Is the boiler temperature set high enough? Could your roomstat have been faulty from day one?
Again, as others have said, the system may simply need tweaking and balancing...

We do cover parts of Reading. PM me if you get stuck, and we may be able to pop over and have a look.

 

[Blackcatgas]

I initially thought the same but the new pump is 180mm between the connections and this is larger than the one already fitted. Therefore the system will need to be drained and the pump connections redone so I thought that was probably the time to redo the flow and return.

I dont claim to know more about the boiler than pottertons own engineers but.... Potterton only recomend the 35mm pipes within 300mm, I could recomend that you put on another coat before you go outside instead of just a jumper but youd be "ok" without it.
If you were to do a test with the new pump, then the new pump fitted to the boiler with 300mm of 35mm flow and return then I bet my toothbrush that you wouldnt be able to tell the difference.
Make sure that the rest of the system is piped up in size corectly as said in previous posts, 28mm to the first 7+ rads.

 

[sijones]

I dont claim to know more about the boiler than pottertons own engineers but.... Potterton only recomend the 35mm pipes within 300mm, I could recomend that you put on another coat before you go outside instead of just a jumper but youd be "ok" without it.
If you were to do a test with the new pump, then the new pump fitted to the boiler with 300mm of 35mm flow and return then I bet my toothbrush that you wouldnt be able to tell the difference.
Make sure that the rest of the system is piped up in size corectly as said in previous posts, 28mm to the first 7+ rads.

Looking at the installation instructions for the boiler they state that 35mm pipes should be used for the flow and return to within 300mm of the boiler. I think they mean that everything should be 35mm until 300mm (max) from the boiler. I have attached a schematic from the installation manual.

 

[sheff paul]

I dont claim to know more about the boiler than pottertons own engineers but.... Potterton only recomend the 35mm pipes within 300mm, I could recomend that you put on another coat before you go outside instead of just a jumper but youd be "ok" without it.
If you were to do a test with the new pump, then the new pump fitted to the boiler with 300mm of 35mm flow and return then I bet my toothbrush that you wouldnt be able to tell the difference.
Make sure that the rest of the system is piped up in size corectly as said in previous posts, 28mm to the first 7+ rads.[/QUOTE







Failing that rent out the rooms with the cooler radiators.....

 

[Blackcatgas]

Looking at the installation instructions for the boiler they state that 35mm pipes should be used for the flow and return to within 300mm of the boiler. I think they mean that everything should be 35mm until 300mm (max) from the boiler. I have attached a schematic from the installation manual.


View attachment 4234

Ahh yes that makes sense, I thought that you were going to just cut in 300mm of 35mm off the boiler then just conect back into 28mm.
Instaed of a repie in 35mm maybe split the system int 2 zones then conect them into a low loss header off the boiler.

 

[sijones]

Is the boiler temperature set high enough? Could your roomstat have been faulty from day one?
Again, as others have said, the system may simply need tweaking and balancing...

We do cover parts of Reading. PM me if you get stuck, and we may be able to pop over and have a look.

The boiler temperature is on maximum and the room thermostat appears to be working fine.

I will be in contact with you soon to arrange a suitable time for you to take a look.