# Heavenly Pressure



## tAClue (Jul 6, 2017)

A couple of questions regarding pressure ladies and gentlemen.

How accurate can I expect the gauge on the Heavenly to be?

Also, am I getting enough pressure?

Once the boiler gets up to temp/pressure...

....it switches off here at 1.1bar......

  

......then it falls to here, about 0.83bar before heating up again.

  

Does this all look right or is the pressure (assuming the gauge is correct) on the low side for this machine?

I'm also assuming that this is a pressure adjustment screw like on an air compressor (there is usually a plastic cover over this with a hole for the screw). Does this need adjusting if the readings on the gauge are correct?

  

Thanks once again to all those taking an interest.


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## stevenh (May 15, 2014)

Not sure what the proper pressure range is for your machine but the behaviour is correct as all Pressurestats have a deadband, partly to stop it from switching constantly if it hovers around the set point. Most have deadband around 0.2-0.3 bar. Depending on your temperature requirements, you can increase the boiler pressure by adjusting that screw but I'll let others comment on what the maximum value is.


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## El carajillo (Mar 16, 2013)

The pressure should be between 1 and 1.2 bar when fully warmed up. The screw in the centre of the P /stat allows you to adjust this (they can become "sticky" as they get older) make a note of the screw head position before adjusting to enable resetting as a small change can make a considerable difference. (it may be worth adjusting the screw up and down considerably to free up mechanism/ contacts.

Do not set temp/ pressure too high as the boiler safety valve is set to 1.6 to 1.8 bar.


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## tAClue (Jul 6, 2017)

I forgot about the pressure being different at the boiler and the group head. The pressure at the group head is the important one for pulling shots (please correct me if I'm wrong). How do I go about measuring that?


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## El carajillo (Mar 16, 2013)

You are correct this is the important pressure for brewing

To measure pressure at the brew head you need a suitable pressure gauge to attach to your P/F in place of the spout, this is then used without a basket in the P/F. Machine is turned on as for brewing coffee and gauge measures /reads pressure at P/F.

The pressure is adjusted via the OPV / expansion valve inside the M/ch.

Check adjusting OPV on Gaggia Classic ---not exactly the same but shows principle.


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## 4085 (Nov 23, 2012)

Just to make sure and sorry if I am lecturing you, the boiler heats up to a point where the stat kicks in and the boiler stops heating. It then reduces in pressure to the lower point when the stat tells the boiler to kick in again and the cycle starts. I think as stated, that 1.1 to 1.2 is about right and it will kick in again at 0.8 or 0.9


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## tAClue (Jul 6, 2017)

El carajillo said:


> You are correct this is the important pressure for brewing
> 
> To measure pressure at the brew head you need a suitable pressure gauge to attach to your P/F in place of the spout, this is then used without a basket in the P/F. Machine is turned on as for brewing coffee and gauge measures /reads pressure at P/F.
> 
> ...


Is there a well known and recommended gauge available for purchase? Also is the thread to attach said gauge universal/common?


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## El carajillo (Mar 16, 2013)

The thread is 3/8" BSP, an oil filled gauge damps out any flicking caused by vibe pump. You can obtain a gauge with the correct thread or use an elbow with a 3/8 BSP female to whatever thread your gauge has often 1/8 BSP or 14" BSP.


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