Do you know where the tenant is or where he works?
Practically if he is gone then I would enter, no point on compunding your losses. Was the ESB/Gas put in his name, if yes he may have closed the accounts to get his deposit back, unless he's run up a horrendous bill and plans on not paying, check with them. Ask the neighbours when they last saw him etc. You need to do some detective work.
Before you enter the house I'd send an email to the PRTB stating that the tenant has deserted the property, that he doesn't reply to your emails/texts, house calls etc and that he hasn't paid the rent and that you fear (for example) that the house will get damaged due to frost so you are entering the house. That way the tenant cannot pretend that you evicted him. When you check out the house you will know if he is really gone, a TV is nothing, he might have gone on holiday for a couple of weeks with the TV, but if he left personal items behind he is likely to return. Take pictures and proof of date of entry and a witness. If he is not gone, leave the house immediatly without touching anything and go down the proper notice route of serving proper notice.
The above practical advice is what I would do as a landlord, it is not in any way legal advice.