# Water pressure on a 747



## Walton (Nov 22, 2006)

I have just purchased a 747 and I have found that when you turn on the hot water, after 10 secs there is a blast of air in the system and takes about 40 secs for it to clear and pressure to be restored.
Dealer said that the tank hadn't been blead when filled. He left it over night and guess what, air in the system.
I took it to another place and he replaced the non return valve at the cold tank. It still causing air in the system after a couple of hours.
Is their a non return valve at the alde heating side of the water pump?
Any help would be appreciated as my wife laughs at me after coming out of the toilet after a shave with the front of my shirt and trousers splashed with water.


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## Bubblehead (Mar 5, 2007)

Hi Walton

How old is your 747 and how long ago did you purchase it? If its got a waranty take it back and tell them to sort the problem out as it has an air leak somewhere on the system.

If thats not an option the go round the system and check every joint you can find and check the condition and tightness of it. Also check for any water leaks.

Another issue may be that the system hasnt been fully bled (does this happen every time or only after filling the tank from near empty? We had a problem with our last van (Aviano) where it was a BU&&er to get rid of the air when filling after draining you had to fill the tank slowly and allow the water to vent from all the taps starting with the lowest and finally the shower. It was also important to move the taps from hot to cold and back to allow all the air out and to fill the hot water tank.

You also mentioned the wet heating, Im unsure about the non return valve. I think its totaly seperate as its a glycol mix in that pumpped around I dont know about the means of heat exchange though. Have you bled the heating at all? We did ours and its made a hell of a diffrence to the heat output.

If this is all tosh, sorry, Im sure that a 747 expert will be along soon

Andy


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## Walton (Nov 22, 2006)

Thanks Andy for the info.

I am going upto dealer this morning to collect the motorhome. I will make sure the system is well bleed and I will get him to check the heating as well.

The 747 is 2008 with 3000 miles. Fully loaded. It was a really good deal as the Rimor that I traded was fully loaded as well, so I did not have to start a source goodies again!!!!!!  

Walton


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## inkey-2008 (May 24, 2008)

Hi Walton
We have the older version 747. I think you need to run the hot tap to purge the air from the system it can take a while.

We have had the same problem when we switch off the electrics the dump valve opens and dumps all the water from the system. I removed the dump valve from the system as we go to Spain for the winter and never encounter very cold weather so no fear of frost.

Andy


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## 120994 (Mar 3, 2009)

Hope your dealer isn't RDH - see company reports - looks like they are no longer trading but have turned into auctioneers


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## 125353 (Jul 4, 2009)

Any luck resolving this? We have the same problem as yourself. 

Same year, 2008, and also from N.ireland. Bought from Thompsons.


We had the same problem in easter this year, so we left it in and all was fine. But now we're on the road and its happened again.


Somebody has suggested we check for a sort filter around the water pump, but we can't seem to get at the pump. It sounds like its between the toilet waste wank and the rear storage. Have looked everywhere possible without ripping stuff out but no luck.

Any ideas??? 

:?


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## inkey-2008 (May 24, 2008)

If they are in the same place as mine you will struggle.
Mine are under the kitchen the only way to get to them was to wiggle up under the floor and then I could only look at them as I could not move. 

I thought the previous owner had put them there ( I have 2 don't ask why) I have just had a new door put in the side of the van to access them. And a electric isolater.

They do have a small filter on them if they are the same as mine. We had problems but we found that it cleared it self we run all the taps including the shower.

Andy


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## 125353 (Jul 4, 2009)

@ Andy

I don't think I'll goto the bother of getting to the pumps then, lol :lol: 


Did running the taps solve your problem for good or short-term? And did u run them all on hot or cold?


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## inkey-2008 (May 24, 2008)

No problems now and I do not let it run out of water now just to be on the safe side. The addition of another locker door opens up a whole new area of the van.
I was worried that they would pack up when we were away for the winter and that would have been hard to resolve.

It will also let me reroute the heating ducts as we have a diesel heater where the gas heater was in the front and the heat was being lost between the floors due to poor instillation of the ducting.
Andy


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## 125353 (Jul 4, 2009)

Will give the taps a go in the morn as the kids are in bed. Will post an update then.

Thanks for the info Andy.


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## Walton (Nov 22, 2006)

I left my motorhome into Leisure Technical Solutions in Dromore to get an alarm fitted. I mentioned to him of the water pressure problem.

The non return valve at the water tank access in garage was changed, but did not solve the problem.

The problem seemed to be more the hot water and if left say overnight, suddently a gush of air soaking me at the w/h basin in the toilet in the morning while shaving.

Simon did find another valve on the other side of the van near the boiler in the cupboard. This seemed to resolve the problem, but we were motox at the weekend which the van was used only for the day, tanks had enough water from the previous weekend, and hey presto more air locks.

Once bleed, seemed okay. Going away motoxing this weekend and staying overnight, I will know better.

SMG747 if you want any further info pm me your mobile!!

Hope this helped

Walton


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