Of course we carry a spare pump, so when the water flow reduced I recognised the signs and sure enough a couple of days later there was no water in the kitchen or bathroom. The replacement is quite quick but that’s not the point, the pump should be better made. 

When the last pump failed I proposed replacing it with a ‘proper’ diaphragm type pump, but found that there was a problem finding suitable adaptors to attach the pipes to the pump because it had American threads that are not used a lot in the UK. I am now revisiting the design and have a different solution that I will show when the job has been successfully completed.

Watch this space . . . 

Later note: I’ve just finished installing a diaphragm pump, what a difference! The old Reich Twin pump is rated at 19 litres per minute with a pressure of 1.4 bar ( 21 psi), our new pump is a Seaflo rated at 15 litres per minute with a pressure of 3.6 bar (55 psi). Water flow is more that twice as much and it makes no difference whether I measure the flow into the bathroom sink or with the shower head in the raised position. I will prepare a page with further information in case anyone else wants to replace their Reich submersible pump with a diaphragm pump.

The pump actually has BSP (British Standard Pipe) threads, so I was about to purchase hose connectors that screwed into the pump and then use plastic hose. In the event the pressure generated by the new diaphragm pump was so high that some water escaped via the pressure relief valve of the Hymer heater. I solved this by fitting a low cost pressure reduction valve. To the non-technical readers this probably sounds like a lot of trouble, but it’s worth doing to save the inconvenience of having NO water.

Normally there would be 50 or more motorhomes spending the night there, but now the road is blocked and all the facilities have been ripped out. When we searched the internet we found reports that the site has been taken over by Camping-car Park, a membership organisation!

Our experience of trying to book one of Camping-Car Park’s sites was terrible, in short you have to be a member and pay various fees which meant that our one night was going to cost us around €50 which is far too much. We used to be members of both the Caravan Club and Caravan and Camping Club but found their rates far to costly so we now refuse to join either.

We will not be using Camping-Car Park either. A quick search using our phones produced a really good aire a short distance from Calais where we passed a quiet night without cost.

When we’re on the road we don’t need electric hook up and all the other facilities provided by many campsites, our needs are few, so aires are our preferred overnight locations. 

Temperature now showing

Following on from my previous post about the Hymer outside temperature showing —°C, after extensive research on the internet and various forums the problem has been fixed.

The problem was the external temperature sensor, the sensor had failed, that problem was not really difficult to diagnose. The bigger problem was finding the location of the original external temperature sensor on the Hymer (Fiat Ducato). In fact the sensor has still not been located.

The base chassis is a Fiat Ducato, (X290 is the Fiat designation for the base vehicle). This is used by Hymer is Germany to built the finished motorhome. As far as the electrics of the vehicle go, Fiat provides a series of large connectors that link into the Fiat Ducato electrical system. Hymer then add their layer of electrics on top, using the Fiat connectors. This starts to get complicated because Fiat use one set of wire colours and Hymer use a different set of wire colours.

After an extensive search of the vehicle, under the bonnet, under the vehicle, inside the driver’s door and the mirrors the original external temperature sensor could not be found. More searching on the forums found a post where the vehicle owner had been unable to located the original temperature sensor and so decided to cut off the appropriate wires and install a completely new external temperature sensor and connect it to the original wires. That is what I did. The most difficult part was determining which wires needed to be used.

• Carefully studied the Fiat Ducato Converter’s Manual that shows the electrical connections.
• Found the appropriate connector on our Hymer and established the correct wires that go to the external temperature sensor.
• Cut the wires and attached a variable resistor set to 10k ohms, this is to confirm that these are the correct wires.
• Purchased a replacement thermistor temperature sensor.
• Constructed a new external temperature sensor housing and found a suitable location on the Hymer.
• Attached the new sensor and installed wires to connect it.
• Tested and confirmed it works.

Not a quick and easy fix but very satisfying in the end. The original sensor is still somewhere on the vehicle but can’t be found.

I have put together a page of photos and more information about this project, here.

Temperature showing —°C

When I collected the Hymer from its MOT a couple of weeks ago I noticed that the temperature had reverted to ‘normal’ so it was showing around 9°C, I thought that maybe something had been reset during the MOT, no such luck, by the time I arrived home, just 4 miles later, the temperature had climbed to an unseasonal 36°C.

Last week we did a week away in the Hymer, mid-March so temperature were either single figures or up to about 14°C, the temperature shown on the Hymer instrument panel was ridiculously high, but then it changed to —°C, just three dashes. This suggests to me that the external temperature sensor has failed. Not only that, but there appeared to be a problem with the cab heater too, we had to turn up the temperature to 32°C to get any warmth coming into the cab. That suggests that the two temperatures are linked in some way.

I am now researching the problem with the help of google and will update this post when more is known.

Keywords: Fiat Ducato external temperature sensor problem

Here’s a photo of the actual fuse that was causing the problem and stopping the 12 volts getting to the heating element. The blackening of the yellow plastic part of the fuse has been caused by the fuse body being heated over a long period of time. The Hymer motorhome is 8 years old and this is the original fuse. 

The ‘hidden fuse’ from our Thetford fridge

This fuse is hidden, and as I said, VERY difficult to access. It is located on the underside of the printed circuit board in the base of the fridge. If you are not competent in taking equipment apart, do not attempt a repair or replacement of this fuse. 

For more information about how to test the fridge and check out all the connections please read this page here on ourtreks.uk. There are detailed instructions and photos that show where this fuse is and how to check the connections. An electrical test meter is needed and Torx screwdrivers.

Last time we were out in our Hymer I noticed that when the engine was running the Thetford fridge freezer was not running off the 12 volts from the engine. The fridge freezer can work off gas, mains electricity or 12 volts; it will only work from 12 volts when the engine is running because the fridge uses a lot of power. Changeover between the 3 power sources is automatic, the Thetford fridge selects the mains first, if mains is not available it uses gas or 12 volts.

At the moment, November, it’s not a huge problem that the fridge will not work off 12 volts, there is obviously nothing wrong with the fridge cooling because it works off mains or gas, it’s only the 12 volt that is not working. 

A quick search on the internet revealed that this is a fairly common problem which means there are a lot of forum posts from people whose motorhome fridges don ‘t work on 12 volts. I spent a LONG time trawling through long threads of conversations and reading them carefully to understand what might be the cause of the problem.

The number one cause of most people’s motorhome fridge not working on 12 volts was a fuse on the main fuse panel, I went and checked all the fuses but didn’t find any fault. Back to the internet and a LOT more reading.

Fault diagnosis is ongoing. First I checked all the fuses on the Hymer’s electrical panel, a lot of fuses, but non of them was blown.

Next came some internet searching to review what other people had experienced. My first guess is that the 12v heating element is not working. That means either there is no power getting to it, or the 12v heating element is damaged, blown but simply open circuit.

I’m waiting for a fine day to do some more checks with a test meter, I’ll update this post as soon as I know more.

To recap the story of our water problems . . . our Hymer B544 came equipped with a Reich Twin motor pump; that pump worked until August 2022, 6 years, so we had no real complaints about how long it worked. We spend a lot of time in our motorhome, so the water pump gets a lot of use.

We replaced the pump by another Reich pump because the first had given good service, although I did consider changing from a submersible pump to a Shurflo diaphragm pump. One of the reasons to stay with the Reich submersible pump was that we had a long trip to Spain and Portugal booked and I would have had to make the changes to the water system before we went. With all that in mind we ordered a new Reich pump from Caratech at Lincoln, it arrived quickly and was fitted very easily. The flow and pressure were much better than the original Reich water pump so we were very happy.

Unfortunately that happiness did not last long, 6 weeks later while we were at Sanxenxo in northern Spain the pump stopped working, I could not believe that it failed in such a short time. I contacted Caratech immediately and they were very helpful, advising that we should return the failed Reich pump for a refund when we returned home, but in the meantime we should do whatever was needed to acquire a new pump.

My first task was to find the appropriate Spanish words to add to my vocabulary and then go to speak with the site owner. I explained that nuestra bomba de aqua (water pump) no funcionaba (was not working).  He was most accommodating and said he could order a replacement via Amazon and it would be delivered quickly (Prime). We were planning to move on, but stayed at Sanxenxo extra nights until the new Reich pump arrived. A second pump in only 6 weeks, that was hard to believe. However, that pump worked and we continued our holiday trek returning home in early October 2022.

Caratech refunded the cost of the Reich pump and the long months of shrinking day-length began. We had short motorhome stays parked on the driveways of our children to provide childcare and enjoy Christmas. As the day-length started to increase we wanted to get back into the Hymer, so at the end of February we booked a short break in Worcestershire at Clay Farm Motorhome and Caravan Site. Imagine our predicament when on the first night the water pump failed to deliver any water.

I checked the fuse, it was not the cause. Next I listened carefully, no sound from the pump. I lifted the pump out of the water tank, still no sound. The impeller was jammed, so I carefully tried to turn it and the pump sprang into life, but that was short-lived. The Reich pump did work, but only in a horizontal position, as soon as it was returned to vertical in the water tank it stopped, and after a couple of times even that brief activity stopped.

So there we were, our first night away but no water for food preparation, no hot water for washing etc. Yes, we managed with a watering can and heating water in a kettle on the stove top, but it’s not convenient. We stayed two nights then abandoned the holiday and went home.

I have contacted Reich pumps via their website to explain the problem. The pump has failed but I don’t have an invoice that I can show to demonstrate when it was purchased. Will Reich believe my account of what has happened?

The original Reich pump failure

Click any photo to enlarge

[See image gallery at ourtreks.uk] I like to know what has gone wrong with anything that fails, in the case of the water pump I cut it open and discovered that water had got into the motors and corroded them.

The Third Reich pump to fail

Reich submersible pump lifted out of the water tank

Close up of the pump

As this pump is likely to go back to the maker I don’t want to cut it open to find out what has gone wrong. However, I can report that some of the water that came out of it was dirty, so I suspect that water has gone into the pump and caused corrosion.

This could be a manufacturing problem.

Portugal did not live up to expectations so we cut our losses and drove back into Spain.

We will build the web pages and add them to this site as soon as possible with tips and reviews about the places that we stayed.

Spain and Portugal Trek – click to enlarge

I’m pleased to report that the water flow in the Hymer is now better than ever, especially in the toilet bowl where the water swirls around noisily.