Mains C/H pump & inverter.

[Biggles]

I while back I saw mentioned that someone was using standard mains C/H pump on its own dedicated inverter.

 

I am thinking this might be a better system than the one I have on my Mikuni which is bloody noisy to the point it wakes me in the morning when it clicks in 45 feet away by resonating in my bedroom radiators.

 

What's the pros and cons of this setup? I am thinking the inverter would power up and then start the pump so the inverter was only on when required.

 

What would a typical setup like this draw?

[Lucien]

A typical 'traditional' mains powered heating circulator using an induction motor will take upwards of 35W on low speed, corresponding with about 4A battery consumption at 12V. This compares unfavourably with the 1-1.2A of (say) a typical Johnson or Jabsco 12V circulator but then the mains unit will probably offer a greater flow rate and head even on low speed. However the new generation of high-efficiency mains circulators with permanent-magnet motors can operate down to around 10W, which puts them on a fairly equal footing with the DC types. Of course with power this low one must also take into account the idling losses in the inverter if that would not otherwise have been switched on.

 

Lucien

[Happy Go Lucky]

I fitted a mains C/H pump to my last boat and it did work very well. It was a 70' boat and I couldn't get enough circulation from 12v pumps at a price I could afford. The mains pump was free A simple relay activated from the original 12v pump connections fed power to the inverter.

 

The only problem with this setup was that I originally used a little modified sine wave inverter. This ran OK but was quite noisy and I suspect that the motor wouldn't have lasted that long. Shortly afterwards I fitted a pure sine wave inverter to supply the whole boat and used the relay to feed power to the pump. After this it worked perfectly (and silently).

 

As liveaboards with children we left the inverter on all the time we weren't connected to shoreline (so that the kids could turn the games consoles on without waking us up). If you turn yours off at night then you will either need an inverter with a remote switch on facility or use a more substantial relay/contactor that will cope with the inverter current draw. There may be small pure sine wave inverters nowadays but, at the time, 500W was the smallest I could find and that was a bit expensive just to run a pump.

 

However, our Mikuni still used to wake us up in the morning but it was the noise of the burner rather than the pump. We were closer to it than you are though.

Edited October 20, 2012 by Happy Go Lucky

[John V]

I think it was probably me that made the entry about using a 240v pump.....my boat is a bit unusual, as it is a Humber barge with a very large area to pump the water round, also all the lighting is 240v low energy (I designed it many years ago, before LEDs were affordable, when folded fluorescents were the power saving choice ) so my pure sine wave inverter runs all the time and supports the fridge as well, the inverter has a standby current of about 1 amp at 24v. As my home berth has shore mains and I have a main generator, a wing generator and an ancient dedicated 24v charging generator......as I said my situation is not typical. All I can say is that the inverter is 12 years old and the central heating pump lasted about 6 years before seizing up and being replaced by another cheapo from the local plumbing shop and apart from a slight hum and the odd gurgle the system is almost silent.

edited for clarity

Edited October 20, 2012 by John V

[Gibbo]

The noise you're getting isn't coming from the water pump so changing that won't make any difference.

[John V]

Gibbo I know this is off topic but... your excellent explanation of battery charging, does it hold good for lead calciums as well? with a very primitive system mine have lasted 10 years so is it worth going high tech? thanks

[Gibbo]

Gibbo I know this is off topic but... your excellent explanation of battery charging, does it hold good for lead calciums as well? with a very primitive system mine have lasted 10 years so is it worth going high tech? thanks

 

If they've lasted 10 years, carry on doing exactly what you're doing. Don't change a thing!

[John V]

If they've lasted 10 years, carry on doing exactly what you're doing. Don't change a thing!

 

Thanks I owe you a pint

[Biggles]

The noise you're getting isn't coming from the water pump so changing that won't make any difference.

 

Hi Gibbo. I think in this case and I am putting my tin hat on here, but you are wrong! There I've said it! As much as you would be welcome aboard my boat to date I've not seen you there, and certainly not in the bedroom at 6am (when you would be most unwelcome) when the pump starts.

 

I know it to be the pump as the start cycle is water pump on for about 15 seconds while the glow plug heats up then the fuel pump and fan motor start then after about a minute the glow plug goes out and the sequence is done.

 

It's the noise from the 1st 15 seconds that wakes me up not the rest of it which at 45 feet away and several walls in between attenuate.

 

It just to see why you think its not the pump, I'd be interested to hear.

 

I rung Mikuni about it and they said to return the pump and they would "adjust the magnets". Which seems to me that they know to be a problem.

[Gibbo]

Hi Gibbo. I think in this case and I am putting my tin hat on here, but you are wrong! There I've said it! As much as you would be welcome aboard my boat to date I've not seen you there, and certainly not in the bedroom at 6am (when you would be most unwelcome) when the pump starts.

 

I know it to be the pump as the start cycle is water pump on for about 15 seconds while the glow plug heats up then the fuel pump and fan motor start then after about a minute the glow plug goes out and the sequence is done.

 

It's the noise from the 1st 15 seconds that wakes me up not the rest of it which at 45 feet away and several walls in between attenuate.

 

It just to see why you think its not the pump, I'd be interested to hear.

 

I rung Mikuni about it and they said to return the pump and they would "adjust the magnets". Which seems to me that they know to be a problem.

 

Then your water pump is broken. They are almost silent. I know, I'm on my fourth one and not a single one has ever made even the slightest noise. Now the air pump on the other hand! That's like a jet engine that resonates through the boat, down the piping, everywhere.

[Biggles]

Yeh it's deffo the CH pump. As I say it resonates through the rad and is at the start of the cycle. The air pump can be heard but only just.

 

Can adjusting the magnets solve this. Sounds a bit odd to me TBH.

 

So what about an alternative 12v pump that's going to be quiet.

[Gibbo]

Yeh it's deffo the CH pump. As I say it resonates through the rad and is at the start of the cycle. The air pump can be heard but only just.

 

Can adjusting the magnets solve this. Sounds a bit odd to me TBH.

 

So what about an alternative 12v pump that's going to be quiet.

 

I don't think the magnets can be adjusted. Yours might be different, but they certainly can't on all the pumps mine has gone through throughout the years.

 

All four of mine have been silent. Noisy water pump on those is not the norm (the norm is the entire thing actually not working at all).

 

There is a good side to replacing the pump with an AC one powered from an inverter: You'll then be able to concentrate on worrying about the air motor when that breaks instead (because it will)

[smileypete]

I while back I saw mentioned that someone was using standard mains C/H pump on its own dedicated inverter.

 

I am thinking this might be a better system than the one I have on my Mikuni which is bloody noisy to the point it wakes me in the morning when it clicks in 45 feet away by resonating in my bedroom radiators.

 

What's the pros and cons of this setup? I am thinking the inverter would power up and then start the pump so the inverter was only on when required.

 

What would a typical setup like this draw?

Are the TRVs or lockshields on all the rads closed down? Wonder if it makes more noise under load.

 

Edit: Also is the heater and pump at a high point in the system? Maybe air is collecting and getting sucked into the pump.

 

cheers, Pete.

~smpt~

Edited October 20, 2012 by smileypete

[Biggles]

The pump is about level with the mid point in the rads maybe on the upper end of mid.

 

It never made a noise until a few weeks ago. All the system valves are open and the TVR' are now on full as its getting colder now.

 

I am fairly sure there is no air in the system. The highest point is the top of the towel rail which is about 3' above the hight of the rest of the system.

 

It was interesting when I rang Mikuni they seemed to know what it was and how to fix it but it means sending back for "service".

 

I am considering going for a Hurricane 2 TBH, just they are a mental price IMO.

 

I don't think the magnets can be adjusted. Yours might be different, but they certainly can't on all the pumps mine has gone through throughout the years.

 

All four of mine have been silent. Noisy water pump on those is not the norm (the norm is the entire thing actually not working at all).

 

There is a good side to replacing the pump with an AC one powered from an inverter: You'll then be able to concentrate on worrying about the air motor when that breaks instead (because it will)

 

How many? Over what time?

 

Another thought occurs to me as we'll, if I have an independent pump I could switch it on when the engine is heating the calorifier the Mikuni coil could act as a heat exchanger and dump some heat inside in the cold weather. The water in my calorifier is mentally hot.

[bottle]

Sorry to just take this piece :

 

the TVR' are now on full as its getting colder now

 

but why?

 

I thought the idea of TVR's was you set them to the number (which is related to room temperature) that you want and leave them there.

 

ie. they work as a room stat. turning them up or down does not make the room hotter or cooler any quicker.

[Phil Ambrose]

The noise you're getting isn't coming from the water pump so changing that won't make any difference.

 

Agreed, the clicking is more than likely the fuel pump on the Mikuni, it is a solenoid pump and each click is the pump supplying a measured amount of fuel. There was an extensive thread about this recently.

 

Phil

[Biggles]

Agreed, the clicking is more than likely the fuel pump on the Mikuni, it is a solenoid pump and each click is the pump supplying a measured amount of fuel. There was an extensive thread about this recently.

 

Phil

 

 

Nope this is defiantly NOT the clicking of the fuel pump. This can barely be heard at any time.

 

It's definitely a whurr.

 

Sorry to just take this piece :

 

the TVR' are now on full as its getting colder now

 

but why?

 

I thought the idea of TVR's was you set them to the number (which is related to room temperature) that you want and leave them there.

 

ie. they work as a room stat. turning them up or down does not make the room hotter or cooler any quicker.

 

I like it hot! Normally set the stat at 23° Also the MX60 goes into half power mode once the returning water is at ??c. This makes it quieter and cheaper and kicks in quicker with the TVR's on full. This in its self is a better way of regulating the temperature.

[Happy Go Lucky]

Just as a coincidence I picked up an old computer USB pack today. This seems to produce a pure sine wave and is rated at 200W.

 

This one was being thrown out because it wasn't quite up to the load of the latest computers and so I got it free. With some modification to connect it up to the boat 12V supply rather than an internal battery, this might be suitable for running a heating pump.

[Gibbo]

How many? Over what time?

 

It's on its 4th one. But that will last quite a while because something else is broken now and I'm not throwing any more money at it. Biggest sack of shit I've ever come across.

 

I found the water pumps used to last about 2000 hours. If I made my stuff last 2000 hours I'd have been bankrupt years ago.

 

Just as a coincidence I picked up an old computer USB pack today. This seems to produce a pure sine wave and is rated at 200W.

 

This one was being thrown out because it wasn't quite up to the load of the latest computers and so I got it free. With some modification to connect it up to the boat 12V supply rather than an internal battery, this might be suitable for running a heating pump.

 

I assume you mean UPS?

 

Check the battery voltage. A huge number of them don't operate on 12 volts. 24 or 36 volts is more common. There are some 12 volters, but not as many.

[Biggles]

So here's my thoughts

 

One of these Pump

 

Control:- from the Mikuni water pump power a relay to switch the main inverter on for the duration of heating requirement.

 

I already have auto remote switching on the inverter it would just mean putting another make relay in this line.

[smileypete]

The pump is about level with the mid point in the rads maybe on the upper end of mid.

 

It never made a noise until a few weeks ago. All the system valves are open and the TVR' are now on full as its getting colder now.

If the hoses rise away from the heater the air should rise out too, but if it's only recently starting being noisy maybe something has got caught in the impeller.

 

Maybe worth pulling the pump and inspecting inside, also testing with a bucket of water and some hose, see if it still vibrates a lot then.

 

cheers, Pete.

~smpt~

[Gibbo]

It never made a noise until a few weeks ago.

 

Is this not a clue?

[Lucien]

That Wilo Smartpump you linked goes down to about 40W at minimum (perhaps a bit lower if the flow is throttled) so maybe budget 50W from the battery. This is about the same as the total consumption of an MX60 so if you change the pump (which at the moment might account for 12W) you'll be slightly less than doubling the system's electrical consumption. I don't know if this would make any difference to you as I don't know your battery capacity etc. As with fridge compressors etc, mains variants have historically been designed for simplicity and low cost but not ultimate efficiency. More efficient mains pumps are now available such as the Wilo Stratos that goes down to 9W. Whichever you use, it should do much better than 2000 hours!

 

Lucien

[Biggles]

Is this not a clue?

 

Indeed it does. But before removing it for a week away servicing it then possible £140 + vat replacement etc.etc. I thought I would mine the combined knowledge and experience on the CWF to see if there was experience of this issue which the is case, and there seams to be no home fix.

 

Also someone in the future might benefit from this thread.

[Biggles]

That Wilo Smartpump you linked goes down to about 40W at minimum (perhaps a bit lower if the flow is throttled) so maybe budget 50W from the battery. This is about the same as the total consumption of an MX60 so if you change the pump (which at the moment might account for 12W) you'll be slightly less than doubling the system's electrical consumption. I don't know if this would make any difference to you as I don't know your battery capacity etc. As with fridge compressors etc, mains variants have historically been designed for simplicity and low cost but not ultimate efficiency. More efficient mains pumps are now available such as the Wilo Stratos that goes down to 9W. Whichever you use, it should do much better than 2000 hours!

 

Lucien

 

 

There is a massive difference in price. Wilo Stratos

 

I have 1180a/h but of course any draw that can be minimised is to be considered. When we are on the boat the inverter is on anyway, the auto switching is purely for turning it on before we get to the boat and for the 5c frost protection mode.

 

Is this pump worth the extra cost?