Baxi Luna 310 fi - HELP PLEASE!!!

Seikon

So we've just moved into a new place that came with this machine. It's a combo one, but we only use it for hot water heating.

Problem is...

It only works on certain taps/when there's enough flow.

We literally have to turn on the kitchen sink to have the bathroom faucet have hot water.

Even in the kitchen where it kicks in 60% of the time, it takes a long while for it to even get hot (at least a minute).

So, any solutions? Thoughts?

We had a guy come by today, he wasn't much help.

The machine doesn't seem to have much pressure (on the gauge) when off or active. From what I can gather, maybe it needs to be re-pressurized? I'm not sure how to do that.

Thanks for your help.

kcopp

Classic symptom of the diaphragm in the flow switch is bad. It needs to be replaced. Part is relatively inexpensive.

Leon82

Are you on a well? Those have minimum pressure and flow requirements

Seikon

Not a well, no.

Thanks for the information kcopp. I'll look into that.

I did forget to mention that the guy who came today mentioned that the gas pipe is only 1/2" and it should be 3/4". Is that an issue/contributing to the issue?

kcopp

No not really.

Tom_133

I agree with Kcopp that its the diaphragm, but someone should test to make sure you are getting good gas pressures, and the burner is happy. I have had several Baxi's act crazy due to gas pressure.

neilc

is it possible the faucets not getting hot on their own are "low flow", 1/2 gallon a minute, and not tripping the flow switch ?
maybe try removing the aerator and seeing if increased flow allows hot to be hot.
then you would need to slightly open the flow restrictor,
or maybe you find the aerator or restrictor fouled by debris.

superdave

If the boiler fires off with 2 taps open then yes it is diaphragm. When you have the Tec. out to change it you should also make sure the expansion tank has the right PSI in it. Make sure he test the gas in coming is right PSI and run it on full DHW temp and flow to see if the gas PSI drops!! Last is to have him set up the gas valve on high fire and low fire this will help keep the DHW from big swings on temp and stop the boiler from going off and on. What is the size of the heat load??

Seikon

Thanks for the help so far guys!

I had a guy come over. He was relatively useless.

I do have an update and a couple more questions in regards to responses I got here.

So...I was able to Google my way into putting the pressure gauge to the right level. That actually seems to help to make it fire more consistently. I removed the aerator from the bathroom sink and that one finally actually gets hot water (hadn't ever since we moved in 3 weeks ago).

There definitely seems to still be a water pressure issue. To get the Baxi to fire the taps seem to have to be full blast or the machine won't recognize it.

On top of that, yeah all taps get hot water, but it still takes 1 minute often to get hot water even when it does activate. Gas line?

@neilc how do I open the flow restrictor?!

@superdave heat load? No idea!

Thank you.

Espioechis

For one... what is the make and model of machine?
2 what is gas supply?
3 what is fixture demand?
4 what is incoming pressure?
5 is there a pump?
6 is there a prv(after all it’s not a well)
7 is this an instant heat unit n have you maintained it?
8 do u have a softener

Espioechis

You don’t even mention if it’s the hot or cold w no pressure. Or both??? So many questions...

Seikon

So, I'm a rookie. So I don't know too much. So...

Also, the make and model is in the title.

Also, I'm pretty confident I was clear that the only way (before re-pressurize) to get hot water was to turn on 2 taps.

kcopp

Here is the part.... get someone to install it. Done.

http://bostonheatingsupply.com/5405330.aspx

Seikon

Thanks!

You're confident all my symptoms lead back to this?

kcopp

99% sure.

neilc

Seikon said:

@ neilc how do I open the flow restrictor?!

blockquote>
From the Aerator, it's that little washer looking thing with the small hole in it, just expand that hole a little,
or it's a series of holes around that disc, expand a few of them,
a sewing needle, or teeny drill bit, knife tip(exacto), or, what ever works for you,
just poke it in there and wobble it around a bit.

Another thought,
at the Baxi, is there an inlet screen on the cold supply?
and that needs cleaning ?

superdave

I agree 99% if unit turns on after 2 or more taps are open. It is diaphragm. This part does see a lot of hot and cold water so it can break down over time like a water closet flapper. It take 40-50 water temp. then turns it into 120. Where are you located??

Seikon

I'm in London, Ontario, Canada.

Thanks for all the help!

I assume this is not something I should attempt on my own? Like, replace the diaphragm?

kcopp

I would not... unless you are super handy. At least you can describe the issue to a qualified contractor.

superdave

Try www.wallhungboilers.com
They are up your way and should be able to help out

Seikon

Yeah, I've spoken a little to them. Plan on this week again.

Thanks again!

Seikon

Okay, so just confirm before I spend more money on this thing..

Diaphragm should fix both the not always activating due to low flow, as well as it taking so long to heat up?

I really just want to make sure before hiring someone new.

Thanks!

superdave

It should fix activating the boiler on DHW. But the time line depends on the total pipe run length.

Seikon

Okay, thank you.

Our house really isn't that big, so the length of time to get hot water seems excessive.

Is that possibly another issue? Does that maybe have to do with the 1/2" gas pipe as opposed to 3/4" pipe?

superdave

That is why you should have someone set up the boiler on high and low fire to make sure it is running right.

superdave

When boiler is set up it will ramp up and down as needed to be more consistent hot water and heat.

Seikon

Hey @superdave , I'm a little confused by the high/low gas thing.

This is a setting within the machine?

superdave

Yes You need to set up boiler with a gas manometer (Digital).
This will help keep it from short cycling.

Seikon

Me again.

So attempt number 2 with a tech (they sent out a new person for free) with Enercare (local company) to try and fix our Baxi. This guy was slightly more useful, but only marginally.

He said the machine seems like an older one and that he wouldn't advise putting any more money into it. I do have the serial number, is there a way to check how old the machine is?

He has a good point that if it's super old. But I also don't want to not put a couple hundreds bucks into it if it lasts another couple years ya know?

Any help (again!) would be great, thank you.

Tom_133

Did you or he change the diaphragm?

SuperTech

> @Seikon said:
> Me again.
>
> So attempt number 2 with a tech (they sent out a new person for free) with Enercare (local company) to try and fix our Baxi. This guy was slightly more useful, but only marginally.
>
> He said the machine seems like an older one and that he wouldn't advise putting any more money into it. I do have the serial number, is there a way to check how old the machine is?
>
> He has a good point that if it's super old. But I also don't want to not put a couple hundreds bucks into it if it lasts another couple years ya know?
>
> Any help (again!) would be great, thank you.

This sounds exactly like what an incompetent technian does, or a crooked one. If he's incompetent then he's trying to upsell you on a replacement boiler because he can't figure out what the problem is or doesn't have the tools, knowledge and skill to figure it out. So he tries salesman techniques....if he's crooked he probably knows it only requires a minor repair but is trying to upsell you on a new unit to make a sales commission.

I always try to repair the system unless it's unsafe to operate or needs major repairs like a heat exchanger or compressor. This way my customers know I'm looking out for their best interests and can trust me when I make a diagnosis or recommendation. The customer should always be a to make the decision whether to repair or replace the system and be given prices before any work is performed.

kcopp

I don't get it.... Its a simple fix

Seikon

@Tom_133

I wish I/someone could change the diaphragm!

No one in this area seems to know a thing about these machines. Very frustrating.

superdave

Where are you located?? Have someone change out diaphragm and check the NTC sensor to make sure it is reading right temp. set gas PSI on high and low fire should be in and out less than 2hrs.

gerrydini

I'm having the very same problem. How did you resolve your problem. Was it the diaphragm? Thank you

Alan (California Radiant) Forbes

Sounds like it was the diaphragm or maybe a microswitch that works in conjunction with the diaphragm. However, it's important to know that Baxi no longer supports 310 Fi heaters as well as some of their other products. Circuit boards are no longer available.

Seikon

> @gerrydini said:
> I'm having the very same problem. How did you resolve your problem. Was it the diaphragm? Thank you

Weirdly, it turns out we didn't really have an issue.

We had just bought the place and for some reason the machine had lost it pressure. We upped that and it sort of worked as it should.

I say sort of because it still doesn't activate at times. Turns out that's because our new energy efficient taps don't have enough flow to actually turn on the machine. We literally have to turn on another tap in the house to get hot water in the bathroom.

Tom_133

When what you describe is happening, its typically one of these items. From most likely to least.
1- diaphragm/microswitch, these tell the boiler to turn on when water flows.
2- the venturi in the 3 way valve, this has a filter on it and they break apart very easy
3- the inlet valve as a nut on the end, that has a filter that can be plugged,
4- the plate exchanger can be plugged, or parts from the venture can get stuck in it after it breaks.