under sized boiler ???

[Ermintrude]

I was going to mention the GA digital gas valve

 

[happyflyer]

The problem is simple, you can ramp the gas valve up and down and the fan speed, but getting the combustion air volume to match the gas is beyond the electronics in a domestic boiler, I think they still do a good job of getting it near to how you would do it commercially or industrially.

 

[IDCHAPPY]

The new Vokeras have a 1:10 modulation

 

[Nostrum]

From Vokera

The Unica i range boasts an enviable modulation ratio of 10: 1, this high ratio enables the boiler output to be reduced to as little as 10%. For example the 28kW Unica i can reduce its output to just 2.8kW, so when the home only requires 3kW, the boiler will modulate itself down to 3kW. Boilers with an inferior ratio, for example 4:1 would only reduce to 7kW, resulting in wasteful ON/OFF cycling and reduced efficiency. A high modulation ratio can significantly reduce wasteful on/off cycles, which in turn, will increase component longevity and helps to ensure stable domestic hot water temperatures.
In simple terms; 10:1 modulation = better fuel efficiency, increased component longevity, optimal comfort.


So there you go, this is why boilers shouldn't be oversized.


Oh, but I still wouldn't fit a Vokera..

 

[happyflyer]

I worked for Hamworthy 40 years back on the Dual fuel Rotary Cup burners up to 20,000,000 Bthus in old money, flame length up to 15ft long, turn-down about 30 to 1, in the days before GSR and Corgi when men were men, the noise from the burner caused most of my tinnitus 99dB+ , we used 50 gallon oil barrels as the outer core for the silencers on the main air intake, a client was posh if they had silencers fitted, now you would get drummed off the plant, at hamworthy we perfected an excess oxygen cell, it controlled excess oxygen in the flue gases perfectly, the burner air damper had a small slave damper on it this was operated by the cell, you guys with your 25 kws gas boiler meeeow.

 

[Ermintrude]

The new Vokeras have a 1:10 modulation

Like that's going to work..... Vokera? What they mean is boiler will fire 1 in 10 attempts after first year! Well efficient. Auto anti cycling and it never overshoots temp curve!

 

[happyflyer]

From Vokera

The Unica i range boasts an enviable modulation ratio of 10: 1, this high ratio enables the boiler output to be reduced to as little as 10%. For example the 28kW Unica i can reduce its output to just 2.8kW, so when the home only requires 3kW, the boiler will modulate itself down to 3kW. Boilers with an inferior ratio, for example 4:1 would only reduce to 7kW, resulting in wasteful ON/OFF cycling and reduced efficiency. A high modulation ratio can significantly reduce wasteful on/off cycles, which in turn, will increase component longevity and helps to ensure stable domestic hot water temperatures.
In simple terms; 10:1 modulation = better fuel efficiency, increased component longevity, optimal comfort.


So there you go, this is why boilers shouldn't be oversized.


Oh, but I still wouldn't fit a Vokera..

That's the way, where are they made not in the UK!!!

 

[Dotty]

I worked for Hamworthy 40 years back on the Dual fuel Rotary Cup burners up to 20,000,000 Bthus in old money, flame length up to 15ft long, turn-down about 30 to 1, in the days before GSR and Corgi when men were men, the noise from the burner caused most of my tinnitus 99dB+ , we used 50 gallon oil barrels as the outer core for the silencers on the main air intake, a client was posh if they had silencers fitted, now you would get drummed off the plant, at hamworthy we perfected an excess oxygen cell, it controlled excess oxygen in the flue gases perfectly, the burner air damper had a small slave damper on it this was operated by the cell, you guys with your 25 kws gas boiler meeeow.

Now you're talking my language.

Thought I loathed and despised rotary cup burners with a deep and abiding passion, was glad to see my last one go a few years back.

 

[happyflyer]

Now you're talking my language.

Thought I loathed and despised rotary cup burners with a deep and abiding passion, was glad to see my last one go a few years back.

Haven't seen one for years but I would bet a lot of money there a load still going in India at lot when out there in the 60s, a real engineering job. I worked as Area Manager for Selectos for 3 year went over to Dublin to service potato crisp oil heaters they were the size of a London bus, we would fire it from one end and the flame would be about 2ft in dia and 12-15ft long oil only in Dublin there was no gas then.... lads don't know there born, used a fork lift truck to take the burner off it was that heavy.

 

[Nostrum]

Alright you condescending old git!

Go and learn how the remote control for your video recorder works!

:83:

 

[Dotty]

Alright you condescending old git!

Go and learn how the remote control for your video recorder works!

:83:

That's what we have kids for!

 

[happyflyer]

Alright you condescending old git!

Go and learn how the remote control for your video recorder works!

:83:

Can't do it Nosrtrum too complex let the Grand-kids sort it.... hey and not so much of the condescending, don't mind the old git that's spot on...

 

[Roger Welton]

Haven't seen one for years but I would bet a lot of money there a load still going in India at lot when out there in the 60s, a real engineering job. I worked as Area Manager for Selectos for 3 year went over to Dublin to service potato crisp oil heaters they were the size of a London bus, we would fire it from one end and the flame would be about 2ft in dia and 12-15ft long oil only in Dublin there was no gas then.... lads don't know there born, used a fork lift truck to take the burner off it was that heavy.

Still a few rotary cups going at sea, last ship i was on had 2 down firing running on 360cst fuel, the ignitors used 4.5 gal nozzles to get the things going., they were a major pain for the cups getting clagged up with crud especialy if they were firing for a prolonged period (i.e when you most needed them). I also sailed on a ship with the same burners but firing from the bottom, never had any issues so can only put it down to the extra heat they were exposed to.

 

[happyflyer]

Still a few rotary cups going at sea, last ship i was on had 2 down firing running on 360cst fuel, the ignitors used 4.5 gal nozzles to get the things going., they were a major pain for the cups getting clagged up with crud especialy if they were firing for a prolonged period (i.e when you most needed them). I also sailed on a ship with the same burners but firing from the bottom, never had any issues so can only put it down to the extra heat they were exposed to.

Jolly Roger,

I went across to France on the ferry and it was a hell of a rough crossing, I told one of the Old Hamworthy lads, he said how long was the crossing, I said about 2 hours, he said " I have been longer on one wave" sure you know what he meant Rog. I worked on Stone Vapour boiler as well, bet you have, at least you know what a big boiler looks like Roger.

 

[oz-plumber]

Whats the world coming to?

7:1, 10:1 ratio boilers - to much work, to many headaches.

Lock me in a plant room with a 30 > 40 year old boiler that hasn't been serviced in a while.

I know what I would prefer.