Hideaway 60B FF Boiler – Boiler Temperature Control Use

[G3NDI]

We have a Hideaway 60B FF Ser No 040012477 installed in a pumped central heating and gravity
thermocycle on the hot water tank.

The control unit as in Diagram 1 of the “Instructions for Use, Installation…., 32 pp, ” ( can’t attach
image as I get message “Hideaway60A.jpg Upload failed. You have exceeded your usergroup’s
upload quota of 19.5 KB by 2.26 MB” File is only 22kB??) shows the Reset and Burner LEDs and the
Boiler Temperature Control, a rotary potentiometer with switch. This control is mentioned in a
number of places in the “Instructions…” , such as the Commissioning section, Electrical Supply
Failure,etc. It mentions that the Max position corresponds to about 82 deg C. In the section
“Instructions for Use” it says turn the control to any position between 0 and Max.

There is a thermistor inserted in the boiler water jacket and connected to the control unit PCB.
This boiler does not have an Overheat Thermostat according to extra instructions found on the Vaillant web site
[http://vaillantgroup.intelliresponse.com/glowworm/index.jsp?…..].

My query is what purpose is this Boiler Temperature Control serving and what is appropriate position for
normal use as we have a hall thermostat and hot water tank thermostat controlling a diverter valve? I
presume the potentiometer control output is compared to the boiler thermistor output for some
purpose, but it is not obvious as to which has priority: the hall temperature thermostat or the boiler
thermistor? To ensure the hall thermostat has priority should the control be turned to Max? Does
this thermistor output also switch the burner off if the boiler temperature exceeds the control setting
even if the hall thermostat still calls for heat?

Rodney – G3NDI

[electrofix]

Think I understand what your after

all the thermostats are doing different jobs

hall thermostat is measuring the air temperature in the hall. when the air temp falls below a pre-set temperature it will ask for heat. if it exceeds the set temperature then it will switch off the heat

the hot water thermostat is doing the same sort of thing but in this case its measuring the temperature of the hot water tank normally about two thirds of the way down. since hot water rises when the stat gets to the set temperature all water above the stat will be at the desired temperature

The boiler stat measures the temperature of the water in the boiler. the higher it is the hotter the water will be circulating around your system. the hotter your radiators will be when the hall stat calls for heat. setting this stat lower means slightly lower energy usages but also mean the temperature of the radiators to touch is cooler and therefore more child friendly. The only thing you have to be aware of is how the boiler stat and hot water interact. If the boiler thermostat is at a lower temperature than the hot water thermostat then it would not be possible for the hot water to reach the desired temperature

hope that helps

Dave

[G3NDI]

Thank you, Dave, your comments on the hall and hot water tank follow my understanding.

It is the boiler water thermostat purpose that I find puzzling. The boiler only operates when the hall
and or hot tank thermostats switch depending on my electronic timer/programmer [Honeywell ST6400C]
settings [Off,Timed, Continuous]. If the hall thermostat is calling for heat and the house is cold then I would expect
the boiler to operate for as long as necessary for the set temperature to be reached. This could be a long
time and I would expect the pumped boiler water temperature to rise until the heat loss from the radiators, etc,
reach equilibrium and the house eventually reaches the set 20 deg C (or whatever) and the boiler CH
switches off. This water would not in normal circumstances be anywhere close to 82 deg C, which would
be quite dangerous as you indicate?

If the boiler does not have overheat protection acording to Vaillant, then it seems the rotary control could
be left at any point in its movement. However, I think the programmer must have a level comparator looking at
the boiler and the hot tank thermostats. I have checked the hot tank setting which is ca 60 deg C.

Thus, I suspect, assuming the rotary control is positioned at 60 degC or above, the only purpose of the boiler thermostat
if it goes over 60 deg C is to switch the boiler off , or to close the diverter valve if the CH is still calling for heat?

I had asked the question a couple of weeks ago on the Glow-worm web site but I had no reply.

Rodney – G3NDI

[electrofix]

its purely to set the max temp of the water in the system. if there was no control at all its possible the water could boil. allowing you to control that temp allows you to determine the maximum temperature your radiators can be. The lower the setting the lower the radiator temp will be but also you will not lose as much heat in the system from pipes that may be under floors etc as heat loss is the result of the temperature difference between two points. If your rads are cooler then you lose less heat through the wall

Dave

[Author]

Posts