system boiler installation

[reggie13]

Hi all,

I have decided to upgrade my 20yr old conventional boiler system to vitodens 100-W system boiler. I want to replace the vented H.W. cylinder with new one, and convert the rads to sealed system, as I need to bleed them regularly in winter (usually twice a week). I also plan to get weather comp added

How do you ensure the new system is kept in best working condition (apart from annual servicing) ? What ideally should the installer be doing as part of installation ? There's
power flushing to clean out sludge etc. Is a descaler worthwhile ? Can a sludge filter be added to the circuit and cleaned every year ? Anything else advisable ?


Thanks in advance

 

[transam]

Remember your present system is probably an open system , a sealed system will subject the system to more or greater pressure , & can under certain conditions reach a pressure of 3 bars ??

 

[reggie13]

Thx, Yes it's open. Are you saying that the rad circuit may not be able to handle conversion to sealed ? If so will system boiler work with open rad circuit ?

 

[tamz]

99% of systems are fine converted to sealed but the 1% makes a BIG impression. Don't be frightened off. Any leaks would most likely be minor and be easily found and repaired.
There was a time when the mighty BG would not fit a sealed system blr and convert an open system. They insisted the lot be changed. How they have changed their tune

You can get what is called a regular boiler to fit to open vent. Most of the manus make them.
If you are having to bleed your rads twice a week this indicates a system problem and you should get it flushed (not necessarily powerflushed) before fitting new boiler.
A magnaclean or Spirovent magnetic dirt separator would also be advisable.
If you go the reg blr route your existing feed and vent positions may need altering. A decent heating guy will be able to advise although i know we are thin on the ground

 

[reggie13]

Thx tamz, is the regular boiler the same as my conventional one ? Does building regs view it as efficient and Will I be able to redeeem scrappage allowance ?

 

[darren17]

what heating have you got at the moment
is the existing cylinder single or dual coil

 

[plumbnuts]

The new boiler will work the same as your existing one. To qualify for the scrapage scheme, the new boiler must be A rated for energy efficiency.

PS - And your old boiler G rated and on the EST list of boilers

 

[reggie13]

Darren17: how can I tell if cylinder is single or dual coil ? I would assume it is single

plumbnuts: I was Reading some website that said gravity and conventional semi gravity systems like mine are no longer allowed by building regs. The hot water cicrcuit has to be pumped. So I assumed I have to upgrade to a system boiler (not keen on a combi). Have I misinterpreted it ?

 

[darren17]

do you have solid fuel as well as gas boiler
if the cylinder had dual coil you would see 2 pipes on either side of the cylinder,that is 2 flow & 2 return
you do not have to have a system boiler ,
you can use a conventional open vented as long as the heating circuit is pumped
also if you have to bleed your system on a regular basis
the problems could be
micro fracture on the fitting's
pipe config in wrong placement
dirt in system which is caused by air or oxyginated water being pulled into system
also there is a twin tech filter by fernox called tf1 it does the same as magna-clean and is approx half the cost
check the pipe-work for dirt by using a magnet

 

[reggie13]

Cheers darren17, it's definitely single coil.

There's alot of cream crusty discharge around the lower stopcock thing below the rad pump. I guess the washer/seals have had it.

What am I looking for when doing the magnet test? A build of iron particles which get harder to drag over the length of the pipes?

 

[darren17]

the magnet will not stick to copper
if there are iron oxide particles in the system the magnet will stick to the copper in the spots where it has built up

i would say the crudd you are talking about is only pipe sealer something like boss white

as long as there is only 1 coil you would have no problem converting the system to sealed

you should get your system chemically cleaned with fernox system restorer or fernox ds40 that will take care of the dirt

my e-mail is in my profile

 

[plumbnuts]

Reggie

You are correct on not being able to have a gravity system.

The system will need to be fully pumped but that has nothing to do with the boiler.

A System boiler has the pump inside and an expansion vessel for use on a sealed system.

It seems that you have on open vented gravity fed system at present. This will need updating to accomodate the new boiler.

Cost wise and spare wise, you would be better opting for a heat only boiler which is suitable for use on an open vented sysytem.

 

[reggie13]

Plumbnuts, bit confused now;

Viessmann 100-W is available as combi or system according to their web site. Then there is Viessman 100-W Compact which is heat only. The installation .pdf only has diagram showing only 4 pipes: heating flow, heating return, condensate and gas. How would a heat only boiler give hot water ?

 

[htgeng]

Plumbnuts, bit confused now;
How would a heat only boiler give hot water ?

You have a Y-plan or S-plan installed when the boiler is replaced. I think there is a section in the wiki explaining these controls.

 

[reggie13]

makes sense now, had assumed the heat only boiler was for gas central heating only, and hot water came via electric immersion.

Will get quotes for both heat only and system

Cheers all