Primatic cylinder - options

[bash1978]

Hi,

I have a primatic cylinder and would now like to replace this sometime during the spring/summer for a number of reasons. The key ones being, it doesn't produce enough hot water (growing family, tank is small), I can't use any inhibitors in my heating system and I am trying to get more efficiency from the gravity fed system/reduced re-heat time.

So thats the background, I have an ideal 260 boiler with a gravity fed HW circuit and pumped CH circuit. I also have the pump on the return pipe, which isn't great from what I have read.

So, the question I have is can if i replace my primatic with an indirect cylinder, where on the HW circuit do I need to pipe the new central heating header tank (cold feed/vent) ?

How high does this need to be, is higher better as the current header tank or my cylinder is in the loft ?

How can I make the new cylinder more efficient in terms of re-heat times ?

Thanks

 

[bash1978]

OK, not much luck with the first post.

Can anyone assist on the first bit which is if I replace the cylinder I will need to add a header tank,so can I join the header tanks feeder pipe (to fill the system) onto the HW return to the boiler using a tee just after the cylinder connection?

and can I join the vent onto the HW flow from boiler using a tee before the connection to the cylinder ?

 

[BingoBongo]

OK, not much luck with the first post.

Can anyone assist on the first bit which is if I replace the cylinder I will need to add a header tank,so can I join the header tanks feeder pipe (to fill the system) onto the HW return to the boiler using a tee just after the cylinder connection?

and can I join the vent onto the HW flow from boiler using a tee before the connection to the cylinder ?

are you converting to fully pumped or leaving the gravity primaries?

you will have to specify a gravity hw cylinder (different coil afaik)

 

[bash1978]

yes, staying gravity fed at the moment, as its easier to sort (I think) so will replace the primatic with an indirect 1200x450 (or something like that).

I presume I can always convert to fully pumped afterwards using the above ?

 

[gas_man_gaz]

you would be better converting to fully pumped while replacing the cylinder, what boiler ya got?

 

[londonboy]

An Ideal 260 I'd guess

 

[gas_man_gaz]

lol dint see that

 

[Servotech]

yes, staying gravity fed at the moment, as its easier to sort (I think) so will replace the primatic with an indirect 1200x450 (or something like that).

An old fashioned system, yet simple and reliable.

Your new cylinder will be pre-lagged and therefore much better insulated than the old primatic one was (so you are makng a big saving already).

Fit the new header tank in the loft (generally the higer the better). Take a 22mm expansion off the primary flow then up and over the new header tank and take the 15mm cold feed from the new header tank into the primary return.
No electrics,no mv,no pump, no worries, then just sit back and look forward to 15-20 years of trouble free central heating!

 

[bash1978]

thanks servo, that's really helpful.

So 22mm vent with a tee from HW flow (just before the connection to cylinder), and a 15mm feed on the return. Just making sure the joins can be made nearly anywhere along both those pipes (HW Flow/HW Return) ?

Otherwise I will have to rip up the carpet and floor boards as there isn't much pipework visable. I will have plenty of room once the primatic is out to sort out piping aslong as its fine near the cylinder.

Would a 22mm feed from header tank be better or is 15mm fine ?

I also heard or read somewhere that when piping the feed pipe (15mm or 22mm lol) its worth curving the pipe below the join on the HW return and then back up bit like a "J" any views on that ?

finally, my boiler is a fair distance away from the cylinder, probably got a 9/10m run of 22mm (this was plumbed before we bought the house) I do want to keep it simple but also do want to make sure I get enough heat around the circuit to heat the larger cylinder, hope that isn't too long a run, any views would be much appriciated.

Thanks

 

[mysteryman]

You really should convert this to fully pumped with a proper diverter valve and cylinder thermostat. You'll get quicker reheat and considerable savings on gas.

 

[bash1978]

thanks mysteryman, would I be able to upgrade to fully pumped with what I am proposing in the future ?

If so that's fine, the problem I have regarding the fully pumped bit is that I have to do lots of work moving the pump (as its on the CH return, installing 2 port valves (somewhere without ripping up the floor again and electrics and am not comfortbale with all of that at the moment. the system would be a S plan layout when I have finished, but would like to eventually get to that in the near future.

Aslong as what I am proposing is fine to add to, i'd be happy for now

 

[mysteryman]

Yes, probably. Anything you do now can be altered later.

 

[Servotech]

thanks servo, that's really helpful.

So 22mm vent with a tee from HW flow (just before the connection to cylinder), and a 15mm feed on the return. Just making sure the joins can be made nearly anywhere along both those pipes (HW Flow/HW Return) ?

Servotech
You need to make sure that the new expansion tee is level or above the cylinder connection (so that the primary flow connection won't trap air)
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Otherwise I will have to rip up the carpet and floor boards as there isn't much pipework visable. I will have plenty of room once the primatic is out to sort out piping aslong as its fine near the cylinder.

Would a 22mm feed from header tank be better or is 15mm fine ?

Servotech
No a 15mm cld feed is fine.
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I also heard or read somewhere that when piping the feed pipe (15mm or 22mm lol) its worth curving the pipe below the join on the HW return and then back up bit like a "J" any views on that ?

Servotech
No, don't do this at all
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finally, my boiler is a fair distance away from the cylinder, probably got a 9/10m run of 22mm (this was plumbed before we bought the house) I do want to keep it simple but also do want to make sure I get enough heat around the circuit to heat the larger cylinder, hope that isn't too long a run, any views would be much appriciated.


Servotech
9/10m is quite a long run for 22mm gravity circulation pipes you may be better off fitting a a pump after all - you could always fit one afterwards if it is too slow and wire it independantly of the boiler controls with a off/on switch and cylinder stat to control it.
A little unorthodox I know!!

N'B. By lifting the cylinder you can gain "circulating hight" which will improve "slow GRAVITY circulation" of the primaries.


.......................

 

[namsag]

When you but your cylinder make sure it is suitable for gravity as not all of them are now.
It is your house and skill level here so dont so dont feel presurised into making it fully pumped .

 

[bash1978]

Servotech
9/10m is quite a long run for 22mm gravity circulation pipes you may be better off fitting a a pump after all - you could always fit one afterwards if it is too slow and wire it independantly of the boiler controls with a off/on switch and cylinder stat to control it.
A little unorthodox I know!!

N'B. By lifting the cylinder you can gain "circulating hight" which will improve "slow GRAVITY circulation" of the primaries.


.......................[/quote]

Hi Servo, IF I were to add a pump to this where should it be added on the HW circuit and also would this mean I have to change the CH circuit or can i run two pumps ? I have heard about over pumping issues, is that a problem as I will have two pumps then one for HW and one for CH ?