Hello,
We have recently had a new boiler system fitted which is unvente without any feeder tanks.
Previously, we used to add inhibitors/additives into the feeder tank i the loft (Vented system) for the radiators.
How do we add them now to an unvented system?
Thanks
-- M.Joshi
You can get inhibitors etc in cartridges and inject the contents with a cartridge gun into a radiator vent or via the filling loop on the system.
You can buy a gel form which can be injected into a radiator vent using a mastic gun.
If you want to use a traditional type rather than the overpriced injector type - then isolate a radiator, drain it by loosening the union then after re-tightening it - open up the top bung - if it has one and pour in the additive. then re-open the valves.
If your newer rads don't have top bungs then disregard this.
Two ways. The Fernox system which injects into a rad using a mastic gun, or the much cheaper Wickes system where you get a small pump that removes about
650ml from a rad, then pumps around 500ml of concentrate into the rad.The Wickes system is 2/3rds of the price, and the pump is reuseable. The Fernox system using a mastic gun injects under pressure & I have found the cartridges sometimes leak back where the plunger is, wasting concentrate & making a mess.
In message , John writes
Vertical towel rads in the bathroom are good for this, as the top of these tends to be above all the others. I would then just open the main drain c*ck downstairs, drain off a bit , add the inhibitor.
I've done it as you describe via a normal rad, using a bit of flexible plastic pipe, a suitable threaded fitting on the end and a funnel.
whatever you do, don't forget to check/repressurise the system afterwards
If you want to use a traditional type rather than the overprice injector type - then isolate a radiator, drain it by loosening the union the after re-tightening it - open up the top bung - if it has one and pour i the additive. then re-open the valves. [/i][/color] Vertical towel rads in the bathroom are good for this, as the top of these tends to be above all the others. I would then just open th main drain c*ck downstairs, drain off a bit , add the inhibitor.
I've done it as you describe via a normal rad, using a bit of flexibl
plastic pipe, a suitable threaded fitting on the end and a funnel.
whatever you do, don't forget to check/repressurise the system afterwards
In message , M. Joshi writes
It doesn't matter, just remember that if you remove the vent one to remove the whole plug, not just the vent screw.
It should specify the correct pressure in the boiler manual. Normally they seem to be about 1.5 BAR
If it is going down, and you are having to top up the system to re-pressurise, then there is probably a small leak somewhere
On Wed, 25 Apr 2007 19:27:28 +0100 someone who may be M.Joshi wrote this:-
As I understand it that is in contravention of the rules.
Bear in mind that the pressure varies according to the temperature.
-- M.Joshi
On Thu, 26 Apr 2007 20:04:21 +0100 someone who may be M.Joshi wrote this:-
As I understand it the filling loop should be a flexible hose and it should be disconnected when not in use.
flexible hose which has to be disconnected and why a valve tha opens/closes cannot serve the same purpose?
Thanks
-- M.Joshi
On Mon, 30 Apr 2007 00:11:14 +0100 someone who may be M.Joshi wrote this:-
Not really. Presumably it is to reduce the chance of the water supply being contaminated with central heating chemicals.
It doesn't have to be a flexible hose. It does have to completely break from the mains, in such a way that failure of the isolating valve or the check valve cannot result in water being forced back into the mains. This requires that there's a break in the pipework, except when it's actually being filled. Some combi boilers use an integral key operated filling loop, but when they aren't filling and the key is removed, the middle no-mans- land is open to the air, and if either valve started leaking, it would run out of the bottom of the boiler, not back into the other side.
Filling loops have two valves, sometimes three.
There is a non-return valve on the heating circuit side and that may be accompanied by an isolating valve that you can turn off.
There is an isolating valve on the mains water side to turn on for filling.
If the isolating valve(s) is/are left turned on, which may be unnoticed if the mains pressure is less than the 3 bar of the pressure relief valve, and the non-return valve is less than perfect, there is a possibility that heating water, dosed with various chemicals will find its way into the public water supply (also dosed with chemicals) and render it even less potable than it already is.
It is also true that most are left connected and, when you ring a plumber about a gradual loss of pressure they just say "top it up a bit". Most outside taps are fitted without the mandatory non return valve IMHO. Convenience tends to win over non-enforced legislation!
Oh, I wasn't commending its value and I would be the last to suggest the involvement of bureaucracy and legislation.
I did have an amusing conversation with an excitable Welshman at the Water Resources Council about the use of NRVs on showers and why there is considered to be a need for them even in gravity systems. He explained that "sections of our community" (didn't say who) take the head off of the shower to wash "where the sun don't shine, see". Then, rising to a crescendo, as only Clive Jenkins (of union fame when his differentials were being squeezed) could attempt, went on to say that the hose is dropped into the toilet and someone downstairs might turn on the tap, look you. So there you are.
In my pressure washer selling days I had a running battle with the local water authority about NRV's.
They were insisting that a particular customer ran his pressure washer from a tank with a weir overflow and no ball valve. They wouldn't allow a WRC approved NRV as it apparently didn't meet their requirements.
The machines had a post pump venturi detergent system, so any back syphonage would have had to overcome that, three outlet valves, three inlet valves & a NRV.
They finally claimed that if they shut off the water on a 6" plastic water main, the suction of the pressure washer could cause the main to collapse!
Never did get it sorted.
ROTFL.
Perhaps inserting the business end of the pressure washer - I mean the nozzle that rotates at speed and will strip paint - could have brought an enematic smile to their faces....
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