header tank overflow

jimjimt

Just out of curiosity did your new plumber identify the cold feed in the wrong place or did you have to tell him ?

A sealed system is a better system but you have to consider your heating system is 25+ years old. It will put your pipe work and radiators to the test. So be prepare for a larger budget if your system cannot handle being pressurized and this should be explain to you before work commences.

You have a couple of more options.

Combine the cold feed and expansion. They are also pro companies who have design special fittings and devices for this option. Aerjec de-aerator is one option and their is more.

Also note the expansion pipe is coming of your cylinder and not from the oil boiler so technically not a true expansion for your appliance.

Move the circulating pump to the hot press and move the cold feed in front of it. If you can get a wire to the oil boiler and you can pick up the radiator circuit in the hot press. Most likely not but maybe.

A semi pressurized system.
As in use your small tank to feed your heating system. At the cylinder where the cold feed is teed in put a non return valve on the cold feed. Blank the expansion. Put an expansion vessel on the oil boiler. A lot more forgiving than a full blown pressurized system.

Always more options.

brando75

Firstly jim, that test where i opened valve on expansion then plugged feed in expansion for a few seconds and this stopped the pitching.. i done this with my finger couple of times. I then closed valve off again and since heating is working great downstairs. Whereas before with valve closed downstairs was only working at about 30-40%. Would this suggest there was an airlock or blockage that's now released??

ok, so plumber said even with this cold feed teed to return it should still not be pitching. That more than likely there is another design fault somewhere.He said to seal system but i am little worried about these old connections and fittings so he has suggested semi sealing system which is still fed from expansion tank. With this system can expansion vessel be placed in attic or MUST it be placed on oil boiler like you have suggested.

thanks again for all advice

mloc123

Having the same issue myself at the moment. Water is pumping over into the f&e if I turn the pump above the lowest speed, with the pump on the lowest speed the radiators downstairs do not heat very well.

My expansion pipe could be made 6 inches higher, I am not sure if that will be enough. I am interested in the combined pipe setup. Am I right in thinking the below before and after is correct?

jimjimt

Most likely their was a bit of air there trying to escape.

If the cold feed is behind the pump on the return it sucks. That is the design fault and you proved it yourself yesterday.
The cold feed most be in front of the pump if the pump is on the return. Plumbing basics.

All boilers like to have the expansion vessel close to the boiler. So it would be better beside the boiler.
You will need an air vent in the hot press on the top pipe flow pipe on the cylinder.
A semi pressurized system will suit you best as it is a lot more forgiving than a full blown pressurized system.

Dtp79

mloc123 wrote: »

Having the same issue myself at the moment. Water is pumping over into the f&e if I turn the pump above the lowest speed, with the pump on the lowest speed the radiators downstairs do not heat very well.

My expansion pipe could be made 6 inches higher, I am not sure if that will be enough. I am interested in the combined pipe setup. Am I right in thinking the below before and after is correct?

Where is your pump located ? The first drawing looks wrong, basically the small tank in attic will work like a rad. The second drawing isn't totally right either but it should stop the problem occurring

jimjimt

You would have to mark in where the pump is on the drawings and what direction it is pumping.

I would presume red is the flow and blue the return. Which would indicate that the return is piped to the top of the boiler ?
Which I presume is not the case in reality ?

mloc123

Better diagram now.

So, I presume because the the cold feed is behind the the pump it will always pitch no matter how high the expansion pipe is?

It does not pitch with the pump on its lowest setting but the downstairs radiators do not heat fully. My main options are.. move the feed in front of the pump or T it into the expansion pipe?

jimjimt

Move the cold feed in front of the pump would be the proper way to do it.
But sometimes it is not possible.

I have combined cold feeds and expansions in the past with out any issues.

If you can get the expansion pipe up higher do so. This is always good.

The reason it is not pitching at a low setting as such the pump is at the end of its curve and cannot physically pump over the expansion or suck in from the cold feed.

So if the pump was at setting 3 and your expansion was up high enough it could not pitch. Probably about 8m above the pump i would guess maybe a little more.

So a 5 meter circulating pump can pump to 5 metres in height with very reduced flow rate.

Have a look at a wilo pump curve below,

Dtp79

mloc123 wrote: »

Better diagram now.

So, I presume because the the cold feed is behind the the pump it will always pitch no matter how high the expansion pipe is?

It does not pitch with the pump on its lowest setting but the downstairs radiators do not heat fully. My main options are.. move the feed in front of the pump or T it into the expansion pipe?

Yes either will do. At the moment your small tank in the attic is a radiator. You could also seal the system if there is no solid fuel boiler on the system

brando75

jimjimt wrote: »

Most likely their was a bit of air there trying to escape.

If the cold feed is behind the pump on the return it sucks. That is the design fault and you proved it yourself yesterday.
The cold feed most be in front of the pump if the pump is on the return. Plumbing basics.

All boilers like to have the expansion vessel close to the boiler. So it would be better beside the boiler.
You will need an air vent in the hot press on the top pipe flow pipe on the cylinder.
A semi pressurized system will suit you best as it is a lot more forgiving than a full blown pressurized system.

I'm at this stage opting towards a semi sealed system. The plumber seemed to be talking about putting expansion vessel in attic. Are you suggesting a better place is beside boiler outside in small shed?? If so is this a much more complicated/expensive way to semi seal? or is it more or less same job.

Something else about my current system i'd like to mention. When i moved in 7 years back this was the set up. For some reason my flow and return are piped into kitchen, then go straight upstairs across back bedroom floor and are teed into flow and return near to hotpress under floor. That's the flow and return from cylinder to old back boiler. Is this normal? Would it be causing any problems with efficiency? Will it cause any problems when sealing system? What way should it be piped? Would it be major job? thanks again for all replies

jimjimt

brando75 wrote: »

I'm at this stage opting towards a semi sealed system. The plumber seemed to be talking about putting expansion vessel in attic. Are you suggesting a better place is beside boiler outside in small shed?? If so is this a much more complicated/expensive way to semi seal? or is it more or less same job.

Something else about my current system i'd like to mention. When i moved in 7 years back this was the set up. For some reason my flow and return are piped into kitchen, then go straight upstairs across back bedroom floor and are teed into flow and return near to hotpress under floor. That's the flow and return from cylinder to old back boiler. Is this normal? Would it be causing any problems with efficiency? Will it cause any problems when sealing system? What way should it be piped? Would it be major job? thanks again for all replies

All boilers like the expansion vessel at the boiler. Gives the boiler a better life span. No big job, tee, valve,and pipe to vessel, job done. If for no other reason your vessel will have to be checked every year to insure it is working ok. It will be forgotten in the attic.
The slow death of all gas and oil boilers is a uncharged pressure vessel.
So when you get your boiler service you can get your vessel checked as part of the service.

It would be better for your pipe work to be more direct. Unless you are doing a major renovate in your house probably not reality.

So are all rads working ok, head to toe and in the middle ?
A larger circulating pump can work wonders to give your rads a boost along with a good power flush and clean.

brando75

All rads working except sitting room which is last on system. This rad however does work when i open valve in hotpress so i'm hoping when system is semi sealed and valve is left open this rad will heat. Probably needs balancing also.

Where should these pipes be joining system. Should they come in at ground level and join in at fireplace where old back boiler pump was? I know exactly where they are teed in from previous renovation.. just a matter of small hole in sitting room ceiling and disconnecting. But if i brought in two new pipes from boiler where could i join them in?

jimjimt

brando75 wrote: »

All rads working except sitting room which is last on system. This rad however does work when i open valve in hotpress so i'm hoping when system is semi sealed and valve is left open this rad will heat. Probably needs balancing also.

Where should these pipes be joining system. Should they come in at ground level and join in at fireplace where old back boiler pump was? I know exactly where they are teed in from previous renovation.. just a matter of small hole in sitting room ceiling and disconnecting. But if i brought in two new pipes from boiler where could i join them in?

Hard to say this is where you need an experience plumber to survey and advise.
Pipes in general would be better at a more direct route that going up and down. But their maybe a reason they were done like so.
This is where one would have to see.

mloc123

So I raised the vent pipe the 6 inches I had to spare and it reduced the pitching to a drip.

Dropped the tank level 2 inches and it did the trick. What are my best options for dropping the water level? Is bending the ball cock arm really the best option?

jimjimt

mloc123 wrote: »

So I raised the vent pipe the 6 inches I had to spare and it reduced the pitching to a drip.

Dropped the tank level 2 inches and it did the trick. What are my best options for dropping the water level? Is bending the ball cock arm really the best option?

Bending the ball cock is how all the pro's do it.

Pitching may restart at high temperatures due to water expansion. Have a quick look / check once or twice to insure it is or not.

mloc123

jimjimt wrote: »

Pitching may restart at high temperatures due to water expansion. Have a quick look / check once or twice to insure it is or not.

That was one of my concerns left the heating on for 2hrs and checked, all good.

Threw some sentinel x400 in while I was at it so I will flush out the system fully in a week or so and bend the ball cock.

Dtp79

mloc123 wrote: »

That was one of my concerns left the heating on for 2hrs and checked, all good.

Threw some sentinel x400 in while I was at it so I will flush out the system fully in a week or so and bend the ball cock.

When u say "flush" the system I'm assuming your talking about a proper 1 day job and not talking about draining the x400 and refilling the system??

jimjimt

Pouring sentinel into the tank is not much good unless you drain some water first. As it has no where to go.

Dtp79

jimjimt wrote: »

Pouring sentinel into the tank is not much good unless you drain some water first. As it has no where to go.

He might as well pour it into the toilet if he's not gonna flush the system properly!!

mloc123

I had drained the water down enough to get it into the system.

When I said flush, yeah drain the system down... Fill, drain.. repeat a couple of times. I presume the flush you are talking about is some forced system?

xl500

jimjimt wrote: »

Just out of curiosity did your new plumber identify the cold feed in the wrong place or did you have to tell him ?

A sealed system is a better system but you have to consider your heating system is 25+ years old. It will put your pipe work and radiators to the test. So be prepare for a larger budget if your system cannot handle being pressurized and this should be explain to you before work commences.

You have a couple of more options.

Combine the cold feed and expansion. They are also pro companies who have design special fittings and devices for this option. Aerjec de-aerator is one option and their is more.

Also note the expansion pipe is coming of your cylinder and not from the oil boiler so technically not a true expansion for your appliance.

Move the circulating pump to the hot press and move the cold feed in front of it. If you can get a wire to the oil boiler and you can pick up the radiator circuit in the hot press. Most likely not but maybe.

A semi pressurized system.
As in use your small tank to feed your heating system. At the cylinder where the cold feed is teed in put a non return valve on the cold feed. Blank the expansion. Put an expansion vessel on the oil boiler. A lot more forgiving than a full blown pressurized system.

Always more options.

I am also removing a stove and would like to convert to sealed or semi sealed as above

In the Semi Pressurized system as explained by Jimt above is this just the same as only filling a sealed system to 0.3bar which would be roughly the pressure exerted by my Feed Expansion tank ie take away Expansion tank install Expansion Vessel and filling loop and fill system to 0.3 bar will this reduce the chance of leakage in older system