Need advise on a few issues

[RobKnapp2]

Hi,
Just got back from out first trip in out 1990 Swift Challenger.
Has a great time, and the prep work I put in checking everything a few times paid off i think, and nothing became a major headache or stress, to the point that the wife is currently browsing the web for the next place to visit.
Good times, however, a few issues cropped up that im hoping are simple:
1, I broke the cold tap in the kitchen! More accurately the tap head cracked, and therefore the woodruff key will now not 'latch' into the tap itself without squeezing it hard. - I have seen a new tap unit that looks the same design as what we have, is the plumbing part a fairly straight forward job, or am I better off trying to source a replacement tap head? The wife likes the look to the black and chrome one as opposed to the current brown/beige!
2, The water pressure on the hot seems low. It takes quite a considerable amount of time to come through to the tap, worst on the kitchen as im presuming that has the longest pipe run, when it does come through, it sustains hot for quite a while, although the maximum we have used in one shot is a couple of washing up bowls, but I think the water heater only holds 9L so im presuming that this is ok? The pressure does seem to be extraordinarily low though? Could I change the pump for a higher flow unit? Im not entirely sure what system is fitted, but the pump seems to be hard wired and piped from the outside, and the pump itself fits into the box outside. It doesnt have a plug in system that I have seen on other caravans? We replaced the non return valve before we went away as that was faulty, the joints dont leak as far as I can see. I replaced the water filter shortly before we went away, and to double check that it wasnt blocked, I removed the innards from the old one and tried that temporarily. Is it likely to be something simple? Would a higher flow pump help? Is it normal for the hot to take a while before it comes through? The cold is ok, maybe a second or two before full flow. Would some non return valves fitted near to the taps help?
I understand that the water system we have is discontinued/old so getting spares will become increasingly hard. Is it viable both financially and technically to convert it to newer system?
Thanks
Rob

 

[Damian]

If you can post a pic of your current kitchen tap it would be helpful to be able to advise on replacement.
As for the hot water, you will have a Carver Cascade water heater, which could have a damaged non return valve on the cold water inlet, allowing water to drain back to the aquaroll.
The other possibilities are a build up of limescale in the tank, or a blocked internal waterway in the tank, or partially blocked pipes.

If you replace the tap, which you most probably will have to do, it is just 2 pipes, hot and cold, and the microswitches wiring (if fitted)

 

[raccoon]

Hi Rob, I have a swift challenger 450/5se, a 1990 model. The water presure first, I found that the spout on the taps got clogged up with lime scale and this made it look like the water pressure was low. I just pulled the spout off and changed it for the bathroom one and it was ok then. Changing the taps is a bit tricky to do. You have to get under the sink by way of the small cupboard and try to disconect the wires and pipes, although I think you can take the vents of outside and get your hands in that way. If you get second hand taps from a caravan breakers then try to get some pipe left on and that way you just need to join the pipes under the cupboard.
Hope this helps.
Stewart

 

[Steve L]

Hi Rob.
You have some good tips from Stuart here. After swapping the tap flow nozzel as per Stuart's tip. You could try soaking the blocked one in some Mr Muscle sink un blocker. This will soften the scale and with the aid of rubber gloves and an old toothbrush, you might be able to breath some life into the old one.
I don't know where you're based, but you could try www.caravanbreakers.net they are quite near breacon and the beacons national park, so you could work in a short break for her in doors and visit a breaker for yourself

.

Being Herefordshire based myself, they are only an hour from us and I have used them regularly over the last 15 years. They could very well have an exact replacement for your tap.
As for changing the taps. Because the caravan interior was built in modular form before the sides and roof of the van are fitted, you often find pipe clips and other bits in the most awkward places. While it is a bit drastic, I have found that removing the sink bowel & drainer if they are combined, gives you much better access and then while your at it, you can check the seals on the waste and the sink to worktop areas, and on re-assembly bed it in with new mastic sealant. Stuart's tip on making connection using longer tails on the pipes is also worth considering as it afford's easy access to change or isolate the sink tap in the future.

It might be worth changing the pump for peace of mind as well. Havig done all this (about a morning's work), you will be pretty well assured of a good few seasons of use without trouble. I sorted out our vanity sink on our 05 Abbey using this methodogy 18 months ago and have not had to re-do it yet and we are fulltimers.

Good luck.

 

[ProfJohnL]

Hello Rob,

You should only need to change the pump if its not working properly. Now you tell us the flow on the hot side is poor, but you don't mention the flow on the cold. From the way you have written your post, I assume the cold water flow from the taps is adequate, and by comparison the hot flow is poor.

In essence if the pipework and appliances are all working properly, the flow from both hot and cold should be fairly similar, so by a process of deduction, if the cold flow is OK, then the pump is OK, and there must be something wrong with the pipework or fittings/appliances on the hot side.

Changing the pump without resolving the problem won't really help. Damian's advice is good on this point.

Changing the water system,is something a competent DIY'er can do. There's nothing particularly special, and it can be summed up as a single pump lifting cold water, to supply both cold taps and hot taps via a heater. The most complex part is the pump control, and this is usually achieved in one of two possible ways.

Switched Taps
Where each tap has a microswitch that operates when ever the tap is tuned on. All the switches are wired in parallel, so that any tap opened will cause the pump to run. This system , means that wiring has to be taken to each tap and with so many connections, fault finding can be more difficult.

Pressurised system (1)
Here the pump is controlled by a separate pressure switch located close to the cold water inlet. When ever the pressure in the caravan pipe work is low the pressure sensitive switch triggers a microswitch to turn on the pump. The pump runs even when the taps are initially turned off, so it pressurises the pipe work, until the pressure rises above the switches' threshold. The pressure switch includes anon return valve to prevent water (and pressure) leaking back to the cold water tank. This is probably the most common system used with submersible centrifrugal pumps. The pressure switch may need to be adjusted as the battery supply voltage changes.

Pressurised System (2)
An alternative pressurised system uses a pump with a pressure switch built in. It works exactly as above. The main difference is the pumps are generally Positive displacement pumps, and are mounted inside the caravan. Because of the way the pump works, it can actually cause enough of a vacuum to self prime from an external water tank. The major downside, is the pumps tend to be nosier and vibrate when in use.

With each of the systems, you have to be vigilant to ensure the pump does turn off when it is not required. Running pumps without water flow or dry for more than a few seconds can damage the pump. Micro switches in taps do fail, and with pressurised systems, falling battery voltage can mean the pump is unable to raise the water pressure enough to turn off the pressure switch.

Considering a more powerful pump? Sadly caravan systems will never match the performance of a domestic water system, so you have to accept some limitation on performance. From a practical point of view, the link between pressure and flow of a pump is not always straight forward. Most pumps fitted to caravans are capable of delivering more water than you actually get at the taps.

There are two main limitations, the first is the 'head height' of the tap over the pump. This 'head' creates a back pressure on the pump which the pump has to overcome. The second is the constriction of the pipe work and its fittings which resists flow. These two factors combine to reduce the pressure and flow of water you get at the taps. Caravan water systems can only handle a maximum pressure of about 1.3Bar, before joints may start leaking and pressure relief valves on appliances start to blow, so high pressure pumps will not necessarily produce better flow.

Pumps are usually specified as having a peak flow in L/min, and a peak pressure in Bar. Unfortunately these represent the two extremes of operation. Peak flow at no significant pressure, or peak pressure with no flow. The relationship between flow and pressure is dependant on the design of the pump and it is not usually proportional, so half flow doesn't necessarily mean half pressure etc

Having a spare pump can be a good idea.

 

[TD42]

Just a thought as you say you are new to caravaning. When you fill with water & before switching on the electric water heater,you should open the hot tap & wait for all air & spluttering is expelled from the tap,& the water is running clear.This ensures that the hot water water tank is filled with water & avods air locks once the air is expelled turn off the hot tap & then switch on the water heater

 

[RobKnapp2]

Hi All,
Thanks for all the replies. I meant to put in the original post a thank you to all the people who have posted on these forums, as the information I have picked up has been most valuable, and indeed made things seem a little more second nature. I think if we are honest, the wife, I and the 2.5 year old are hooked. Still really excited to be honest so if I ramble I apologise in advance!
The flow from the cold tap is more than adequate, so I surmised that the pump must be OK, so it pretty much rules that out. Im starting to wonder now if I inadvertantly introduced a kink or a tight bend somewhere when I refitted the hot pipe after changing the non return valve. On the non return valve, is it possible that the new one could have been slighly faulty? Out of curiosity mainly, I did a 'suck and blow' test before I fitted it and it seemed to hold pressure. Is it possible that there is an air leak somewhere that is causing the delay in the delivery of the hot water?
When we bought the van, the chap noted to me that there is an o ring in the taps that can fail, and indeed he also showed me a drawer full of spares, im wondering if one could have failed, causing air to bleed in, although surely the non return valve on the tank wouldnt allow this?
When I 'prime' the system, i turn on all hot taps including the shower (i leave the head in the sink) and as suggested wait for all air bubbles etc to dissipate, then turn on the switch and it lights. Incidentally the water slows proportionally the more hot taps I turn on, that would seem to suggest that the problem would be with the main supply pipe or the heater itself? How easy is it to descale, obviously im presuming that I can just throw some Viakal in there, would it be a vinegar job?
On the tap front, the one we have looks identical to this:
http://www.leisureshopdirect.com/caravan/water/product_32692/double_mixer_tap_-_microswitch_-_brown_tf19.aspx
but with a black rectangular plate beneath it, would either this, or more preferably this:
http://www.leisureshopdirect.com/caravan/water/comet_taps/Comet_NOVO_mixer_tap_with_micro_switch.aspx
be a suitable replacement? Im hoping to try and source one for next weekend as I also need to bottom out the issue with the TV aeiral which I can do at the storage site.
So to sum up, things I probably ought to try first:
Check the pipe routing to make sure the bend radii is 'good'
check the non return valve to ensure that it isnt faulty
try a descale

Thanks again for all the help and advise.
Regards
Rob

 

[ProfJohnL]

Hello Again Rob,

Not such a long answer this time!

Keep viakal away from the system, The Carver Cascade is manufactured from Aluminium. ViaKal will be too agressive. Vinegar would be better/safer..

You can't 'open' the heater to descale it, you need to dose your cold water container with the solution, and pump it through. Leave the solution in the heater for no more than a couple of hours, then flush empty through the drain port, and through thoroughly with clean fresh water.