Fan jets causing boiler issue

[PCS2013]

[SIZE=17pt]Hi guys, first time poster but I’m after a bit of advise / help please. [/SIZE]

[SIZE=17pt]In the summer I changed over to fan jets (the 100 ones), however now I’ve come to use my boiler with them in the winter the boiler doesn’t kick in. I’ve got a 6L LPG boiler. I had to run my water on 35 flow on my digital display when I had pencil jets to ignite the boiler, but now with the fan jets it’s at least 50! And even then it cuts out randomly or sometimes doesn’t restart when I’ve stopped the water on a house. It’s definitely the fan jets causing it as when I ran it just through the hose reel the boiler ignited fine at the original 35 pressure. [/SIZE]

[SIZE=17pt]I like the fan jets as it saves me a lot of water (meaning I can do longer days) and I like the rinse with them so I don’t really want to change them. I can only presume it’s something like the back pressure is to much or not enough with the fan jets for the boiler to operate properly? [/SIZE]

[SIZE=17pt]Does this mean that I need a higher litre per minute boiler (which usually requires a higher water flow anyway). Or are 100 fan jets just not compatible for these boilers? Or is my boiler just not working properly? [/SIZE]

[SIZE=17pt]Hope that makes sense. Any help from you guys would be greatly appreciated.[/SIZE]

[SIZE=17pt]Thanks in advance.[/SIZE]

 

[Iron Giant]

This one got missed so apologies if any lads can help ASAP that would be really good 

 

[spruce]

[SIZE=17pt]Hi guys, first time poster but I’m after a bit of advise / help please. [/SIZE]

[SIZE=17pt]In the summer I changed over to fan jets (the 100 ones), however now I’ve come to use my boiler with them in the winter the boiler doesn’t kick in. I’ve got a 6L LPG boiler. I had to run my water on 35 flow on my digital display when I had pencil jets to ignite the boiler, but now with the fan jets it’s at least 50! And even then it cuts out randomly or sometimes doesn’t restart when I’ve stopped the water on a house. It’s definitely the fan jets causing it as when I ran it just through the hose reel the boiler ignited fine at the original 35 pressure. [/SIZE]

[SIZE=17pt]I like the fan jets as it saves me a lot of water (meaning I can do longer days) and I like the rinse with them so I don’t really want to change them. I can only presume it’s something like the back pressure is to much or not enough with the fan jets for the boiler to operate properly? [/SIZE]

[SIZE=17pt]Does this mean that I need a higher litre per minute boiler (which usually requires a higher water flow anyway). Or are 100 fan jets just not compatible for these boilers? Or is my boiler just not working properly? [/SIZE]

[SIZE=17pt]Hope that makes sense. Any help from you guys would be greatly appreciated.[/SIZE]

[SIZE=17pt]Thanks in advance.[/SIZE]

I think you have basically identified the problem @PCS2013. Your boiler needs a minimum flow rate to kick in. Its part of the boiler's safety features. With those fan jets you are saving water so you are reducing the amount of water flowing through your boiler. If swapping back to pencil jets solves the problem then its the fan jets causing the problem.

Getting a higher flow boiler (8LPM for example) will tend to make things worse as they require a higher flow rate to ignite.

The trouble with fan jets is that they become less effective if your flow rate is too high.

BTW, pressure and flow rate are related but aren't the same. Your controller at 35 and 50 or anywhere inbetween is your rate of flow (how much water your pump is delivering) and doesn't relate to pressure at all. The pressure (calibration) remains the same until you readjust it manually or automatically on Spring controllers.

I'm afraid its probably a choice of either one or the other.  Having worked with very cold water yesterday and stiff hoses, I would probably revert back to pencils this winter if the choice was mine and leave the water savings for summer. But that's me.

 

[PCS2013]

Thanks for the reply spruce, that makes sense. I think that is the only way and I’ll have to revert to pencil jets for the winter.

Thanks for the help ?

 

[jack b]

The trouble with fan jets is that they become less effective if your flow rate is too high

Hi Spruce,  I'm trying to understand how the above works. Why would they be less effective if flow rate is too high, could you help me see this pls........my lpg hot water works without any issues, I think its a 6 litre one. I'm also using the 100 degree fans. Many thanks.

 

[steve garwood]

I have a fogwash water heater. I turn the flow up to 60 (from 50) when I’m using it. 

50 is to low to ignite the boiler consistently imo

 

[spruce]

Hi Spruce,  I'm trying to understand how the above works. Why would they be less effective if flow rate is too high, could you help me see this pls........my lpg hot water works without any issues, I think its a 6 litre one. I'm also using the 100 degree fans. Many thanks.

Sorry @jack b. I'm describing how I feel about fan jets with a high flow. They aren't water saving efficient at a high flow if you rinse with the brush off the glass as both my son and I do. My son plugged into my hose reel today with his pole. His brush also has wide angle jets. The pump controller was set high this morning for myself as I normal work with pencil jets.  I watched as he got a good flow of water down the glass when rinsing but he also had a mist of water spraying into the air. It reminded me of Victoria Falls. Downwind it was like fine drizzle rain. I use a brush with fan jets on occassion, but if the flow is too high, the spray can bring down dirt from above the window frame when rinsing off the glass. For me, that's less effective when I consider the end result. So when using that brush I turn the flow down a couple of notches on our Varistream controllers (5 to 3). A dictionary definition of effective is: successful in producing a desired or intended result.

When I replied to @PCS2013 this morning I did say that if the problem went away when he swapped back to pencil jets, then his problem is related to the fan jets. I don't know if this rectified the boiler cutout issue or not but hopefully we will hear a result one way or the other from @PCS2013. I know from personal experience that fan jets are a good water saving device.

Even although you are using a similar 6lpm boiler it could be that your system works where the O/P's doesn't. The boilers are made from components that can differ slightly even on the same production line so it could be that his boiler has an internal flow sensor which is more sensitive than yours. These gas boilers are a work of art but aren't all made exactly identically. No 2 controllers are the same either and he could also be using a different pump and different hose sizes.

There were often queries from windies using 8lpm boilers as to why their boilers would sometimes work and sometimes not.

I could be that if the O/P bought another 6lpm boiler it would work just fine, or he could be sent one thats 'worse' than he already has. No two items are exactly the same.

I hope I haven't confused you more because I'm good at that. ?

 

[spruce]

I have a fogwash water heater. I turn the flow up to 60 (from 50) when I’m using it. 

50 is to low to ignite the boiler consistently imo

Now that's interesting. I'm sure there was a thread on Peter's site relating to flow rates many years ago when he was importing these. He got a boiler to fire up with a 'trickle' of water. At first he didn't want to do the experiment as he was a high flow advocate when rinsing. I maybe wrong but I think Jeff Brimble was involved in that conservation as he was a master of washing and rinsing a window with a 'thimble' (hyperbole) full of water.

 

[jack b]

Thanks Spruce, you're always good for a very thorough and balanced explanation. ?

 

[spruce]

I've mentioned this before @jack b but it does illustrate how two identical items can be different.

In the mid 1980's a friend of ours worked for our sister company Siemens in South Africa. He purchased 2 identical 'transistor' radios, one for each of the children. They were both Siemens radios so conformed to the Bosch/Siemens quality standards. If they didn't 'Robert Bosch would have turned in his grave'. (That was an expression we used to the German parent company when we believed that a product they made wasn't up the high standard Herr Robert Bosch demanded in those early days when he was still alive.)

On their own each radio's sound quality was perfectly acceptable. But when compared with each other, even a tone deaf person could tell the difference.

 

[windowsurfer]

Just use the red gardiner fan jets. I use them n dont have much of a problem with my 5ltre lpg heater. Cobtroller on at 35-40 percent.