Oxyvent

T

tipperary

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Just wondering would people in general recommend the oxyvent system. I intend to have an oil condensing boiler feeding conventional radiators, with stove with back boiler also connected to the radiators.

Based on the manufacturer's claims it seems to be a good product, but I am wondering is it as good as they claim, and if so why is it not standard in new builds at this stage?
 
Thanks Leo

Had gone through these threads. Most of the comments are quite vague, and I was hoping to hear from somebody who had researched the units properly and had a good idea of whether they 'do as it says on the tin'. Alternatively if anybody has one of these installed, are the claims regarding no more bleeding of radiators and more efficient heating true?
 
I finished a self build this year. I installed 2 oxyvent Cremin Tanks. I have underfloor heating down stairs and rads on the 1st floor, hence the need for 2 tanks.
I am using a Grant 32kW condensing oil boiler, 6 sq meters of flat plate solar panels and 300 litre stainless dual coil tank c/w 3kw immersion

The tanks are working fine. I did not have to balance the system, every port on the underfloor manifold is openened fully as is every lockshield valve on the rads. Each underfloor circuit and every rad heats up with no cold patches.

On the underfloor circuits the heat is very even throughout the house. The flow rate on the manifolds are always up to the max when the circuit is on. Even if all the underfloor cicuits are on together the flow rates on each port on the underfloor manifold are at their max. It is the same with rads. Once the heating system was filled with water & pressurised, i bled all the air out of the system, topped the system up again to 1 bar cold.
Then just turned on the heating, no problems.
You could hear the water gurgling or bubbling for the first few days inside the tanks and immediately after the heating would switch off the auto air release valves on each tank would expel air from the system. After abot 3-4 days the system settled down , no noises and the amount of air in the system seems to have been reduced to very little or none.

The hose is 3700 sq feet approx, this will be our first full winter in the house, so we need to trial the system a bit longer.
I turned on the heating last febuary when the house was far from finished i.e no doors between roops, 3 open fireplaces etc. I filled the oil tank with 900 litres of oil. The heating was on pretty much for the first 5 months up to may to dry the house and turned on the heating again in mid Oct (1-2hours a day since mid Oct). The oil ran low 2 weeks ago. So i had it topped up again. The heating comes on in the late afternoon bfore we get home and thats it for the day.
Thehouse is well insulated, 60 mm platinum cavity wall, 35mm insulation on plasterboard,on the internal side of the outside walls, rockwoll between all floor joists between all floors. The floor is sitting on 4 inch subfloor, 80mm kingspan then a 65mm screed and all floors have edging insulation. But 3 open fireplaces. Also no wallvents. Waste of time and inefficent.
According to the digital room stats the house seems to maintain an average room temp of between 18-23 degrees depending on the weather and how long the heating is on for.

I have so say I am very staisfied with the Cremin Tanks.
I did a lot of research on the heating side of things before we started to build. I found alot of people didn't give a damn what you were doing all they wanted was to sell you their product and in alot of cases they
didn't know much about the product thy were selling.
I met Tim Cremin at one of the self build shows, he seemed genuine and offered alot of impartial advice on heating systems. On the day i purchased the tanks he spent 3 hours at the house and explained everything about the tank, every question I had for him he was able to give an honestanswer which so far have been spot on. He promised me on the day that if I had any questions I was to call him , that he would always answer the phone. He did exactly that each time \i called him.Thats aftersales service.

I have no connection with the man in case any one is wondering, i just met him at the show. He is very genuine and as far as i can tell so is his product.
 
Much appreciated Adkelmac. I think I'm pretty much convinced to go with the system at this stage. I presume some of the less than positive posts in previous threads are probably more a lack of understanding of the system.
 
ADKELMAC said:
.........underfloor circuit and every rad ..........

The hose is 3700 sq feet approx,......
I turned on the heating last febuary when the house was far from finished i.e no doors between roops, 3 open fireplaces etc. I filled the oil tank with 900 litres of oil. The heating was on pretty much for the first 5 months up to may to dry the house and turned on the heating again in mid Oct (1-2hours a day since mid Oct). The oil ran low 2 weeks ago. So i had it topped up again. The heating comes on in the late afternoon bfore we get home and thats it for the day.
Click to expand...

You should post a bit more in the numerous previous threads on underfloor heating as there are people there who would be interested in the heating only coming on in the afternoon and the amount of oil used especially with underfloor. It's unlikely to only be the cremin tank that’s giving you that efficiency, would you put it down to good construction (as you described) and a thrifty approach to setting your heating on off times.

 
To be honest I do think the Cremin tanks make a difference to how the heating system works. If you look at the oxyvent website it explains the effect of removing all the air in the system. From my understanding tiny air bubbles are produced when the boiler heats up the water similar in the system, think of what happens when you boil water in a saucepan; the little bubbles of air coming off the surface of the water. Well the same happens when the boiler is in operation only the air is trapped in the pipe work. Air in the pipe slows down the water/flow speed thus the circulation time is slower.
By trapping/removing the air through the Cremin tanks before the warm water enters the main heating circuits i.e. rads and underfloor circuits, you create a high flow rate which allows the water through the system much faster than conventional heating systems. A high flow rate means the rads and underfloor circuits perform more efficiently. My underfloor heating brings the room temp from a cold standing start to 21 deg in 2 hours easily, the thickness of the sfloor slab is also important (65-75mm with 6mm mesh for strength). The faster you get the floor slab up to temp the better.
Most vendors told me I would need to allow the underfloor heating to remain on all day with room stats controlling the circuits in order to keep the floor slab heated, while this may be true with conventional systems it does not seem to be the case with the tanks installed. Also i do not have any mixing valves installed in the underfloor heating system, they just restrict the flow rate and cost you money. The installation of the tanks do away with all these crazy & expensive control sytems. Also with the tanks installed the return temp of the water to the boiler is higher 6-10 degs than without the tanks. I have checked this against other heating systems in other houses. With a higher return temp the boiler does not cut in and out as much as a normal system. When i first turned my heating system i thought the burner was faulty as it did not seem to be on all the time like other burners. Now i just accept this is just another feature of having the tanks installed.
By the way yesterday evening I set the timer for the heating to come on for 3 hours instead 2 hours. I thought it might be a bit cold last night and wanted to see whow the house would perform. When i came home from work yesterday evening my better half asked me what had i done to the heating, she said the house was too warm and uncomfortble and to put it back the way it was!
You can't win.
 
Can you explain how you do not have a mixing valve in your system. Are you using a buffer tank?
 
I still cannot make up my mind about the Oxyvent. I was very impressed with it's apparent abilities on paper, but my plumber, and indeed UFH supplier, both insisted that 1) there was no need for the Oxyvent tank as the heating system included bleeder (not sure if that's the correct name?) valves whose purpose was to allow air to escape from the system, and that 2. the Oxyvent would reduce the flow pressure to the UFH somewhat.
And to be honest, having asked upwards of 10 plumbers now, only one has ever said he uses/believes in the Oxyvent. But then again, how many plumbers have said to keep the UFH on 24/7 :(
 
Regarding the mixing valve: The water for the UFH system is brought through the second Cremin tank, Between the 2 tanks I fitted a wheel valve on a by pass pipe which is required. The wheel valve adjusts the flow through the by pass pipe. By closing down the wheel valve you will force more mot water flow to the second tank, thus raising the temp of the water entering the second tank and through to the ufh. You can open the wheel valve also in order to lower the water temp to the UFH system. A mixing valve would do the job too except cost more money than a simple wheel valve. My ufh manifold has Temp probes fitted to it so I can monitor the water temp entering and exiting the ufh system.
 
I spoke to the company in person last week and apparently Trinty College Dublin have just carried out tests in connection wiht this system

Perhaps you should talk to them directly to find out some more information on this.
 
Can anyone recommend a plumber familiar with the Oxyvent in or around the Naas area.
 
hi very interesting post, I was considering the tanks when we were looking at oil fired boilers but now we are looking at modulating LPG fired, I suspect that as these boilers do not heat the water to the higher temperatures that less air will be created in the system. I put this one to Mr Cremin and post what he comes back with. BTW good tip on the mixing valves
 
I have it installed - I did it cause I was fed up on bleeding air out of the rads - I installed it a couple of months ago and have not had to bleed the rads yet.

Speaking with various plumbers some would regard as the jury is still out on it... nevertheless I gave it a go.
 
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