# Hymer water pump



## 96155 (Aug 29, 2005)

Anyone fitting a new freshwater pump to their Hymer may be surprised at the low flow from the taps if they didn't note the electrical connections before they took the old one off. I have just bought a new 19L /min pump and thought I would try it in a bucket before fitting . I connected it to battery , Brown to + and blue to - and shot a jet three meters into the air, I reversed the polarity and shot a jet one meter. I thought I would check the polarity of the supply to the pump in the van before fitting and found Brown was - and blue +. This was on a 1999 van but i found the same on my old 1992. It is worth checking this as the pump seems to work at half capacity if same colour cables are connected .
I guess this will be my last post on this site as I pull my tail between my legs and and shuffle back to Neil at Motorcaravanning. co. uk


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## smifee (May 17, 2005)

hi tonto

thanks for the free info. i haven't had to change my pump yet so will print this off and file it with all the other water bumph i have collected.

won't be able to thank you for such info under the new regime so will probably join you with neil & co. seems the best site i've found in looking around today.

mike


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## 89682 (Jun 4, 2005)

Hi All

My 544 of 1993 vintage also has a drain plug in the fresh water tank. Whilst on the subject of water. has any any experience with air getting into the system? I run the taps till they stop spitting and all is well, but if I don't use the taps for an hour or so then air is present again. Anyone got any idea's. The pump is a submersible if that helps.

Regards Herman


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## Maxonian (May 13, 2005)

Hi Herman,

Check the non-return valve. 

Raymond


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## Scotjimland (May 23, 2005)

Tonto said:


> I guess this will be my last post on this site as I pull my tail between my legs and and shuffle back to Neil at Motorcaravanning. co. uk


good plan .. else you in heep big trouble from kemosabe :wink:


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## 89682 (Jun 4, 2005)

Hi Maxonian

I'm not sure that a non-return valve is fitted. The water pump seems to lead directly to the water supply pipes (via the screw on cap). There may be some kind of non-return valve in the line that leads to the thetford toilet (which pumps water very slowly).

Thing is that from time to time the water system works fine, but I can never figure out what was wrong. Anyhow thanks for the info.
Regards Herman


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## 88864 (May 10, 2005)

hello herman had the same problem with my pump, mines 1991 if left for a few hours it would take ages to get the air out, the cure A new pump, they are sealed so you can't repair them,

hope this helps chris


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## 89682 (Jun 4, 2005)

Hi Chris

Thanks for the response. Thing is it is a new pump. One of the twin impeller types which deliver a higher flow rate. The problem is the same with the old pump, which is only a few months old. Have you any idea where a non-return valve might be located? 

regards

Herman


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## Maxonian (May 13, 2005)

Hi Herman,

On my B644 the non return valve is located in line with the output tube from the pump, only a few cm from the circular cap on top of the fresh water tank. It is a grey cylinder about 15mm dia. (similar dia to the tube), about 50mm long. It is secured by two jubilee clips. It has an arrow moulded into it to show the direction of flow.

Raymond


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## 89682 (Jun 4, 2005)

Hi maxonian (Raymond)

No such beastie on my rig. whether that is the cause of the problem is quite possible. having said that the problem sometimes cures itself and the system will work quite happily for some time. I will visit a local caravan dealer and try to get hold of a non-return vale and stick it in, can't make the problem any worse. Thanks for the reply.

Regards Herman


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