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Re: Condensation in a Home Observatory

PostPosted: Tue Mar 03, 2015 8:15 pm
by wayne
The cork matting worked, only....not in the way I expected. I was getting water in from the outside. The cork stained dark at the points the water was getting in. I drilled a hole in the foot of the Observatory at the points where the dark patches were, and squirted in some expanding polystyrene. A few hours later, I cut off the residue with a sharp knife. Problem is now solved. I will leave the cork matting in place. It provides a little insulation from the concrete pad. Besides, if I get a new leak, I can see where it is entering the observatory immediately. A little expanding polystyrene will sort that out too.
Clear skies.
Wayne :thumbsup:

Re: Condensation in a Home Observatory

PostPosted: Wed Mar 04, 2015 12:35 am
by carastro
:thumbsup: :thumbsup:

Re: Condensation in a Home Observatory

PostPosted: Wed Mar 04, 2015 11:14 pm
by BLACKDRAGON
wayne wrote:The cork matting worked, only....not in the way I expected. I was getting water in from the outside. The cork stained dark at the points the water was getting in. I drilled a hole in the foot of the Observatory at the points where the dark patches were, and squirted in some expanding polystyrene. A few hours later, I cut off the residue with a sharp knife. Problem is now solved. I will leave the cork matting in place. It provides a little insulation from the concrete pad. Besides, if I get a new leak, I can see where it is entering the observatory immediately. A little expanding polystyrene will sort that out too.
Clear skies.
Wayne :thumbsup:


It's strange how what you think might be the solution to a problem actually solves the problem but in a different way to what you thought it would!! So you didn't have a condensation problem but a leak problem.......congrats on solving it, Wayne!! :thumbsup:

Re: Condensation in a Home Observatory

PostPosted: Tue Feb 28, 2017 5:26 pm
by tony walnut
Hi Wayne. I have a Pulsar like yours and have identical condensation problems. I too have discarded the plastic floor membrane and am about to seal the concrete with damp-proof paint before putting just the rubber flooring back. Has your cork under-flooring done any good? I think my problem probably stems from moisture rising through the concrete slab and collecting as water under the plastic sheet. With just the concrete exposed it stays touch dry but the dome is covered in condensation which I assume comes from the water evaporating out of the slab. Miracle cures welcomed!

Tony.

Re: Condensation in a Home Observatory

PostPosted: Sun Mar 12, 2017 9:41 pm
by jjb2011
Condensation in pulsar domes is an interesting problem. As far as I understand from Wayne's account, Wayne found that the problem he had was caused by a leak of water from outside to inside, so it was not a condensation problem as such.

Since the installation of my dome in November 2016 I have not laid the floor matting as I wanted to ensure that the concrete base had dried out completely. I installed a dehumidifier (volunteered by a neighbour). After initially running the dehumidifier for a week or so continuously to ensure that the concrete floor had dried out, I then ran the dehumidifier intermittently, to see the impact of the dehumidifier.

In this test I didn't see any condensation on the concrete floor with the dehumidifier on or off. However condensation did occur on the dome when the dehumidifier was off. The condensation ran down the dome, collected on the shelf which forms the running rim of the dome, then ran down the wall and pooled on the concrete floor. I think this is the route for water collection under the floor matting.

What is the solution ? In my view it is not possible to prevent condensation on the inside of the dome unless a dehumidifier is used.If you don't want to incur the cost of running a dehumidifier then consider using a ring of towels or some other method for soaking up the condensation as it pools on the shelf.

JJB

Re: Condensation in a Home Observatory

PostPosted: Thu Dec 21, 2017 3:02 pm
by DeadMan
I also use a de-humidifier (desiccant) which is set to 60% humidity eco mode and runs all year round.

I find it probably uses about £3 a week if left running all the time.

I have never had a problem with condensation with the de-humidifier on but I have had problems with water on the concrete base. The problem with concrete is that it does not absorb water very well so it floats across the surface of your base and gets under your floor.

I have tried several things to try and stop this from happening and the best solution is a black plastic ground sheet on the inside and a foam floor ontop of that.

After a while the ground sheet will develop holes and water will get inbetween the sheet and the floor map but the de-humidifier soon sucks it out of the air.

Interesting Idea with the wooden floor I may give that a try in the summer.

Image

Cheers

DM

Re: Condensation in a Home Observatory

PostPosted: Sun Dec 31, 2017 6:39 pm
by jjb2011
Interesting that you have water under the plastic sheet. I discovered yesterday that while I have eliminated the condensation problem in the dome using a dehumidifier, I still have water under the plastic ground sheet. I have pulled up the floor and found a fault in the silicone seal. It can be seen in the photo.

Image

With the Pulsar dome I have sealed it on the outside and the inside using silicone rubber. So there must be a leak in both seals. It was difficult to seal the joint under the breakout box as it was not easy to reach to the centre, and this inside fault is in a similar position. Consequently water is seeping in and then spreading under the plastic ground sheet. It hasn't come through onto the floor as it is trapped under the ground sheet. Not a good situation as all manor of fungus and bugs will thrive under there when the weather warns up in the spring. I will have to pull it all up, dry it out and repair the seal. I also found hundreds of LadyBird bugs under there, these little blighters have taken over the dome !

JJB

Re: Condensation in a Home Observatory

PostPosted: Mon Jan 01, 2018 1:15 pm
by jjb2011
The dry-out
Image

Image

A great way to start the New Year, but will be big free and dry shortly !


JJB - Happy New Year to all

Re: Condensation in a Home Observatory

PostPosted: Sat Jan 06, 2018 1:04 am
by DeadMan
I did think of perhaps using a self levelling compound on the inside of obsy to raise the level of the floor and sealing it from water ingress.

The only problem with that is if it didn’t work well it would be hard to rectify afterwards.

Re: Condensation in a Home Observatory

PostPosted: Wed Mar 07, 2018 6:53 pm
by wayne
Three years since I last posted on this problem., While the leak problem is solved, I still have cork matting on the floor. I still get some condensation problems, but now the leak is stopped, it is not nearly as bad as before. I have placed a small space heater in the Observatory to keep the temperature about five degrees higher than ambient. This seems to sort out the condensation problem. My next improvisation is to lift the cork matting and replace it with heavy duty reflective underlay, placing the rubber jigsaw matting on the top. I am hoping it will be a little better at insulating the cold concrete floor from the warmer air within. Over the winter, when the weather was bad, I repainted the inside of the dome with Blackboard paint, and replaced a defective strip of red LED lighting. Plans are in place to dismount my telescope, up-end it, to replace the CR2032 battery in the base, which is the original since new. I will also take the opportunity to remove the RA motor and gearbox assembly, to check the meshing with a Vernier gauge, check for excess axial worm movement and reduce any excessive lateral worm movement with the adjustable tensioning spring.
Clear skies
Wayne