Problems with my Rinnai 58e

[Happy Guy]

Hi all,

 

I don't know if anyone has had a similar experience, but I'm having problems with my Rinnai water heater.

 

The boat hasn't been used for months, and now the water heater isn't firing up when there is a demand for hot water. It worked fine before. The pilot light works fine, and I have temporarily removed the water filter in case it was blocked and affecting water pressure. I have also swapped the gas bottles to make sure that the gas pressure is sufficient. I installed the unit a couple of years ago, but I've probably only used it a dozen times, so it seems hard to believe that any of the components have worn out!

 

Now that I've ruled out the 'cheap' solutions I'm guessing it's going to require a more expensive one. I've looked quickly at the spare part prices for these things and they seem pretty high. Can anyone suggest why the unit isn't firing up when I turn on the hot tap? I guess one reason is a split diaphragm, but why would it split after so little use. I should confess that I haven't drained it down until now, so maybe frost has something to do with it, but we haven't had any really hard frosts in the meantime, and in addition I haven't noticed any leaks.

 

Thanks.

Oh, just one more thing.... Is there an easy way to check the water pressure coming out of the tap? It doesn't seem great.... Thanks

[smileypete]

Oh, just one more thing.... Is there an easy way to check the water pressure coming out of the tap? It doesn't seem great.... Thanks

 

Is the water pump inlet strainer free of debris?

 

If all else fails, could find a water standpipe with decent flow and not tooooo high pressure (less than 7 to 8 bar pressure), and connect the water heater inlet directly to it via a length of hose.

 

If you have a calorifer with a 3 bar pressure relief valve (PRV), it can be very handy to have a PRV with a built in pressure gauge, which can give a good idea of the pressure the water heater is seeing:

 

http://www.ebay.co.uk/itm/Emmeti-1-2-Fl-x-1-2-Fl-PRESSURE-RELIEF-SAFETY-VALVE-3-BAR-with-GAUGE-/301509047917

 

The heater needs at least 0.6 to 1 bar operating pressure, can be hard to judge from the tap as the cheaper trendy looking taps can be quite restrictive.

Edited February 21, 2016 by smileypete

[MtB]

 

Is the water pump inlet strainer free of debris?

 

If all else fails, could find a water standpipe with decent flow and not tooooo high pressure (less than 7 to 8 bar pressure), and connect the water heater inlet directly to it via a length of hose.

 

If you have a calorifer with a 3 bar pressure relief valve (PRV), it can be very handy to have a PRV with a built in pressure gauge, which can give a good idea of the pressure the water heater is seeing:

 

http://www.ebay.co.uk/itm/Emmeti-1-2-Fl-x-1-2-Fl-PRESSURE-RELIEF-SAFETY-VALVE-3-BAR-with-GAUGE-/301509047917

 

The heater needs at least 0.6 to 1 bar operating pressure, can be hard to judge from the tap as the cheaper trendy looking taps can be quite restrictive.

 

 

It isn't the tap that creates the water pressure at the inlet of the water heater, it's the pump.

 

And cheap trendy taps with restricted flow cause higher water pressure upstream, not lower.

My own two year old Rinnai failed in exactly the same way. Rinnai diagnosed a jammed water section and wanted to flog me a repair kit for £60-ish IIRC, which I declined having previously had a customer with identical symptoms and the repair kit made no difference.

 

Puzzled how yours can be only two years old though, they stopped making them four or five years ago IIRC!

[WotEver]

 

It isn't the tap that creates the water pressure at the inlet of the water heater, it's the pump.

Mike, the comment about the tap was, I believe, in response to...

Is there an easy way to check the water pressure coming out of the tap? It doesn't seem great.... Thanks

 

Oh, and OP didn't say his heater was only 2 years old, he said he installed it 2 years ago.

 

Tony

[smileypete]

It isn't the tap that creates the water pressure at the inlet of the water heater, it's the pump.

 

Where did I say it was?

 

All I was saying is that certain taps don't have great flow being designed for high pressure mains supplies, therefore the flow from these taps may not be a reliable indicator of pump performance.

 

If the heater doesn't work from a known decent water supply, either the fault is with the heater itself, or possibly there's too much restriction downstream.

 

I doubt the OP wants to replace with a Morco only to find out the fault was with the boat's plumbing all along...

Edited February 21, 2016 by smileypete

[Happy Guy]

Hi, thanks for the advice so far.

 

I started to doubt my own memory, so I looked up the receipt for the unit. I bought it from Hamiltons Gas Products on 16 April 2013. £160 plus flue and fitting kit.... so getting on for 3 years now I guess. Maybe it was an end of line unit? Gosh time flies. It also shows how little I've been using my boat!

 

Anyway, getting back to the point... could frost damage have led to a split in the diaphragm? I had a previous heater fail due to frost damage and it was pretty obvious... water squirting out all over the place!

 

Thanks for the info about operating pressures etc.